ISSN: 1119-1449

Nigerian-German Kainji Lake Fisheries Promotion Project

Technical Report Series 5.

POST HARVEST LOSSES IN THE FISHERIESOF KAINJI LAKE

by Dr. A. A. Eyo

Nigerian-German (GTZ)Kainji Lake FisheriesPromotion Project

footte,71sl i,

k%44011111

March, 1997

ISSN: 1119-1449

Nigerian-German Kainji Lake Fisheries Promotion Project

Technical Report Series 5.

POST HARVEST LOSSES IN THE FISHERIESOF KAINJI LAKE

by Dr. A. A. Eyo

Nigerian-German (GTZ)Kainji Lake FisheriesPromotion Project

footte,71sl i,

k%44011111

March, 1997

ISBN 978-037-004-8© Nigerian-German (GTZ) Kainji Lake Fisheries Promotion Project

New BussaNiger StaterNigeria

ISBN 978-037-004-8© Nigerian-German (GTZ) Kainji Lake Fisheries Promotion Project

New BussaNiger StaterNigeria

ISSN: 1119-1449

Nigerian-German Kainji Lake Fisheries Promotion Project

Technical Report Series 5.

POST HARVEST LOSSES IN THEFISWERIES OF KAINJI LAE

by Dr. A. A. EYO

Nigerian-German (GTZ)Kainji Lake FisheriesPromotion Project

March, 1997

diK71.:_L_ZEETS - At;

ISSN: 1119-1449

Nigerian-German Kainji Lake Fisheries Promotion Project

Technical Report Series 5.

POST HARVEST LOSSES IN THEFISHERIES OF KAINJI LAKE

by Dr. A. A. EYO

Nigerian-German (GTZ)Kainji Lake FisheriesPromotion Project

March, 1997

FOREWORD

The aim of the first phase of the Nigerian-German Kainji Lake

Fisheries Promotion Project that came into effect in May 1993 is to

prepare a fisheries management plan for optimum and sustainable

exploitation of the fish resources of Kainji Lake.

The study was commissioned by the project in realisation of

the importance of reduction of post-harvest losses in meeting

consumers needs for adequate fish both in quantity and quality.

The main purpose of the study is to identify at what stages of

fish handling, preservation/processing and marketing post-harvest

losses occur in order to identify areas of intervention.

It is believed that after implementation of the

recommendations given in this report post-harvest losses in the

Kainji Lake fishery will reduce significantly.

Dr. A.A. Eyo

FOREWORD

The aim of the first phase of the Nigerian-German Kainji Lake

Fisheries Promotion Project that came into effect in May 1993 is to

prepare a fisheries management plan for optimum and sustainable

exploitation of the fish resources of Kainji Lake.

The study was commissioned by the project in realisation of

the importance of reduction of post-harvest losses in meeting

consumers needs for adequate fish both in quantity and quality.

The main purpose of the study is to identify at what stages of

fish handling, preservation/processing and marketing post-harvest

losses occur in order to identify areas of intervention.

It is believed that after implementation of the

recommendations given in this report post-harvest losses in the

Kainji Lake fishery will reduce significantly.

Dr. A.A. Eyo

TABLE OF CONTENTSAcknowledgementForewordList of TablesGlossary of Terms ivExecutive Summary

INTRODUCTION 1

TERMS OF REFERENCE 2

REVIEW OF LITERATURE3.1 Fish Deterioration 3

3.2 Categories of Post-harvest Losses 4

3.3 Fish Handling Practices and theirImplications for Fish Spoilage 5

3.4 Fish Preservation/Processing 7

3.4.1 Fish Smoking 8

3.4.2 Fish Drying 143.4.3 Icing 17

3.4.4 Freezing 19

3.4.5 Cold Stores 20

3.5 Fish Marketing3.5.1 Artisanal Fish Marketing 21

3.5.2 Marketing of Frozen Fish 23

METHODOLOGY4.1 Method of Data Collection 234.2 Sample Population, Sample Size and Sampling

Procedure 244.3 The Questionnaire 244.4 Training of Data Collectors 254.5 Data Collection 274.6 Equipment and Fish Weighing 284.7 Assessment of Fish Quality 28

RESULT AND DISCUSSION5.1 Fish Catch 28

5.2 Fish Spoilage at Checking and Landing 28

5.3 Fish Spoilage according to Gear 30

5.4 Fish Spoilage in Relation to Fishing Time by Gear 355.5 Losses due to Bad Handling 415.6 Fish Processing - and Processing Losses 42

5.6.1 Fish Smoking 425.6.2 Fish Drying 445.6.3 Fish Burning 455.6.4 Fish Frying 46

5.7 Fish Marketing - and Marketing Losses 465.7.1 Fish Sellers 485.7.2 Fish Buyers 495.7.3 Losses due to Packaging and Storage 50

5.7.4 Losses due to Insect and MiteInfestation 51

5.7.5 Situation in Onitsha Market 53

G. CONCLUSIONS AND RECOMMENDATIONS 54ANNEXBIBLIOGRAPHY

TABLE OF CONTENTSAcknowledgementForewordList of TablesGlossary of Terms ivExecutive Summary

INTRODUCTION 1

TERMS OF REFERENCE 2

REVIEW OF LITERATURE3.1 Fish Deterioration 3

3.2 Categories of Post-harvest Losses 4

3.3 Fish Handling Practices and theirImplications for Fish Spoilage 5

3.4 Fish Preservation/Processing 7

3.4.1 Fish Smoking 8

3.4.2 Fish Drying 143.4.3 Icing 17

3.4.4 Freezing 19

3.4.5 Cold Stores 203.5 Fish Marketing

3.5.1 Artisanal Fish Marketing 213.5.2 Marketing of Frozen Fish 23

METHODOLOGY4.1 Method of Data Collection 23

4.2 Sample Population, Sample Size and SamplingProcedure 24

4.3 The Questionnaire 244.4 Training of Data Collectors 254.5 Data Collection 274.6 Equipment and Fish Weighing 284.7 Assessment of Fish Quality 28RESULT AND DISCUSSION5.1 Fish Catch 285.2 Fish Spoilage at Checking and Landing 285.3 Fish Spoilage according to Gear 30

5.4 Fish Spoilage in Relation to Fishing Time by Gear 355.5 Losses due to Bad Handling 415.6 Fish Processing - and Processing Losses 42

5.6.1 Fish Smoking 425.6.2 Fish Drying 445.6.3 Fish Burning 455.6.4 Fish Frying 46

5.7 Fish Marketing - and Marketing Losses 465.7.1 Fish Sellers 485.7.2 Fish Buyers 495.7.3 Losses due to Packaging and Storage 50

5.7.4 Losses due to Insect and MiteInfestation 51

5.7.5 Situation in Onitsha Market 53CONCLUSIONS AND RECOMMENDATIONS 54ANNEXBIBLIOGRAPHY

LIST OF TABLES

Table 5.1: Fish Spoilage (sample) according to Fishing Gear

Table 5.2: Fish Spoilage (total) according to Fishing Gear

Table 5.3: Spoilage of Gillnet Catches according to Fishing Time

Table 5.4. Duration of Fishing with Gillnets

Table 5.5: Spoilage of Longline Catches according to Fishing Time

Table 5.6 Duration of Fishing with Longlines

Table 5.7: Spoilage of Trap Catches according to Fishing Time

Table 5.8 Duration of Fishing with Fishing Traps

Table 5.9: Losses in Weight of Fish during Fish Smoking with"Banda" Ovens

Table 5.10 Loss in Weight during Sundrying of Clupeids

Table 5.11 Loss in Weight During Processing of Burning/Smokingof Fish

Table 5.12 Duration of Storage of Fish by Fish Sellers beforeMarketing

Table 5.13 Quantity of Spoilt Fish Purchased by Fish Buyers

iii

LIST OF TABLES

Table 5.1: Fish Spoilage (sample) according to Fishing Gear

Table 5.2: Fish Spoilage (total) according to Fishing Gear

Table 5.3: Spoilage of Gillnet Catches according to Fishing Time

Table 5.4. Duration of Fishing with Gillnets

Table 5.5: Spoilage of Longline Catches according to Fishing Time

Table 5.6 Duration of Fishing with Longlines

Table 5.7: Spoilage of Trap Catches according to Fishing Time

Table 5.8 Duration of Fishing with Fishing Traps

Table 5.9: Losses in Weight of Fish during Fish Smoking with"Banda" Ovens

Table 5.10 Loss in Weight during Sundrying of Clupeids

Table 5.11 Loss in Weight During Processing of Burning/Smokingof Fish

Table 5.12 Duration of Storage of Fish by Fish Sellers beforeMarketing

Table 5.13 Quantity of Spoilt Fish Purchased by Fish Buyers

iii

GLOSSARY OF TERMS

Artisanal

Fisherfolk

Fish monger

Fish merchant

Fish buyer

Fish processors

iv

Small-scale

Men and women engaged in catchingfish

One who trades on fish

Wholesale fish trader

Fish monger involved in buying fresh,smoked or other forms of processed fish fromfisherfolk or primary fish sellers infishing villages and collection centresalong the Kainji Lake basin.

Men and women engaged in smoking and sundrying of fish in fishing villages. Theycould be fishermen or their wives or fishmerchants who process fish in fishingvillages and convey them to distant marketsfor sale.

Primary fish seller One who engages in the sales of fresh orprocessed fish in fishing villages andmarket centres.

Secondary fish seller One who buys fresh or processed fish fromfish buyers or primary fish sellers atcollection centres and distribute toretailers at the local markets. They couldalso be fish merchants.

Retailer One who sells fish directly to consumersat the market.

Collection centres Weekly markets on the lake shore wherefish are sold wholesale to fish merchants.They may operate once a week or once in fourdays.

GLOSSARY OF TERMS

Artisanal

Fisherfolk

Fish monger

Fish merchant

Fish buyer

Fish processors

iv

Small-scale

Men and women engaged in catchingfish

One who trades on fish

Wholesale fish trader

Fish monger involved in buying fresh,smoked or other forms of processed fish fromfisherfolk or primary fish sellers infishing villages and collection centresalong the Kainji Lake basin.

Men and women engaged in smoking and sundrying of fish in fishing villages. Theycould be fishermen or their wives or fishmerchants who process fish in fishingvillages and convey them to distant marketsfor sale.

Primary fish seller One who engages in the sales of fresh orprocessed fish in fishing villages andmarket centres.

Secondary fish seller One who buys fresh or processed fish fromfish buyers or primary fish sellers atcollection centres and distribute toretailers at the local markets. They couldalso be fish merchants.

Retailer One who sells fish directly to consumersat the market.

Collection centres Weekly markets on the lake shore wherefish are sold wholesale to fish merchants.They may operate once a week or once in fourdays.

ACKNOWLEDGMENT

I am grateful to the Nigerian-German (GTZ) Kainji Lake

Fisheries Promotion Project (KLFPP) for granting me the opportunity

to carry out this study. In particular, I appreciate the remarkable

support received from the Project Adviser, Mrs. Marina Mdaihli and

her editorial work on the manuscript.

I am indebted to the data collectors Mr. E. Adelowo, Mr. J.

Odey, Mrs. A. Wara and Ms. H. Idris for their hard work and

perseverance.

I appreciate the remarkable contribution of Mr. J.P. Thuy who

did the data processing and analysis. I also thank Mr. T. du Feu

for his assistance in the arrangement of the field trips.

I am grateful to Chief E.O. Ita for his contribution during

the design of the questionnaire and Mr. J. Atabor (Wada) who typed

the manuscript.

I thank the respondents, the fisherfolk, the fish processors

and fish traders of Kainji Lake for their understanding and

co-operation.

ACKNOWLEDGMENT

I am grateful to the Nigerian-German (GTZ) Kainji Lake

Fisheries Promotion Project (KLFPP) for granting me the opportunity

to carry out this study. In particular, I appreciate the remarkable

support received from the Project Adviser, Mrs. Marina Mdaihli and

her editorial work on the manuscript.

I am indebted to the data collectors Mr. E. Adelowo, Mr. J.

Odey, Mrs. A. Wara and Ms. H. Idris for their hard work and

perseverance.

I appreciate the remarkable contribution of Mr. J.P. Thuy who

did the data processing and analysis. I also thank Mr. T. du Feu

for his assistance in the arrangement of the field trips.

I am grateful to Chief E.O. Ita for his contribution during

the design of the questionnaire and Mr. J. Atabor (Wada) who typed

the manuscript.

I thank the respondents, the fisherfolk, the fish processors

and fish traders of Kainji Lake for their understanding and

co-operation.

EXECUTIVE SUMMARY

The report gives an assessment of the post-harvest losses in the

Kainji Lake fishery.

The study focuses on Quantifiable information on post-harvest

technology and post-harvest losses from fisherfolk, fish processors

and fish traders operating within the Kainji Lake basin.

Four questionnaires were designed to cover each aspect of post-

harvest technology: fish handling, fish processing and fish

marketing for buyers and sellers respectively.

The questionnaires were administered to a total of 665 respondents

comprising 317 fishermen, 115 fish processors, 125 fish buyers and

111 fish sellers in 45 fishing villacses and collection centres

within the lake basin.

The procedure applied involved counting and weighing the fish

caught by fishermen. Quality was determined by organoleptic

evaluation of the colour, odour and texture of the gills, flesh,

eyes, skin and the entire body of the fresh fish. For processed

fish quality was determined by changes in the odour and texture.

A total of 24,839 fishes weighing 2389.3 kg belonging to 43 species

were examined out of which 10% of the catch by number and 9% by

weight was spoilt at checking and 4% by number and 3% by weight was

spoilt at landing.

Total spoilage of fishermen's catches during handling was therefore

14% by number and 12% by weight.

In the sample gillnet was the dominant gear accounting for 79%.

EXECUTIVE SUMMARY

The report gives an assessment of the post-harvest losses in the

Kainji Lake fishery.

The study focuses on Quantifiable information on post-harvest

technology and post-harvest losses from fisherfolk, fish processors

and fish traders operating within the Kainji Lake basin.

Four questionnaires were designed to cover each aspect of post-

harvest technology: fish handling, fish processing and fish

marketing for buyers and sellers respectively.

The questionnaires were administered to a total of 665 respondents

comprising 317 fishermen, 115 fish processors, 125 fish buyers and

111 fish sellers in 45 fishing villacses and collection centres

within the lake basin.

The procedure applied involved counting and weighing the fish

caught by fishermen. Quality was determined by organoleptic

evaluation of the colour, odour and texture of the gills, flesh,

eyes, skin and the entire body of the fresh fish. For processed

fish quality was determined by changes in the odour and texture.

A total of 24,839 fishes weighing 2389.3 kg belonging to 43 species

were examined out of which 10% of the catch by number and 9% by

weight was spoilt at checking and 4% by number and 3% by weight was

spoilt at landing.

Total spoilage of fishermen's catches during handling was therefore

14% by number and 12% by weight.

In the sample gillnet was the dominant gear accounting for 79%.

II

This was followed by cast net (9%), hooks (7%), fish traps (4%) and

beach seines (1%). Gillnet catches also recorded 95% of the total

catch at landing.

Fish smoking using "banda" was the major processing method

accounting for 88% of the cases. Sun drying was 10% while frying

and fish burning were 1% respectivelyl. More women (57%) were

.involved in smoking than men.

About 21% by number or 15% by weight of fish purchased by fish

processors deteriorated before smoking. Only 1% by number and even

less proportion by weight of fish was lost during the smoking

process.

Clupeids were the only species sun dried on the lake basin. This

activity was carried out exclusively by fishermen.

In marketing, primary fish sellers disposed fish majority using

baskets (49%), basins (29%), cartons (17%) and bags (5%).

Inspecting the different containers above it was discovered that

14% of the fish packed in cartons, 12% of the fish stored in basins

and 2% of the fish in baskets was spoilt. There was no spoilage

among fish bought in bags (usually Clupeids).

Fish were stockpiled for one week by 46% or two weeks by 47% of the

primary sellers before marketing.

During this time, some of the fish suffered from mould and insect

infestation resulting in a loss of appr. 6% by weight of dried fish.

1 Fish burning usually followed by hot smoking in "banda" producesblack traditional product which was said to be firmer than normalsmoked fish although losses in the nutritive value was inevitablefrom the burning process.

IIThis was followed by cast net (9%), hooks (7%), fish traps (4%) and

beach seines (1%). Gillnet catches also recorded 95% of the total

catch at landing.

Fish smoking using "banda" was the major processing method

accounting for 88% of the cases. Sun drying was 10% while frying

and fish burning were 1% respectivelyl. More women (57%) were

.involved in smoking than men.

About 21% by number or 15% by weight of fish purchased by fish

processors deteriorated before smoking. Only 1% by number and even

less proportion by weight of fish was lost during the smoking

process.

Clupeids were the only species sun dried on the lake basin. This

activity was carried out exclusively by fishermen.

In marketing, primary fish sellers disposed fish majority using

baskets (49%), basins (29%), cartons (17%) and bags (5%).

Inspecting the different containers above it was discovered that

14% of the fish packed in cartons, 12% of the fish stored in basins

and 2% of the fish in baskets was spoilt. There was no spoilage

among fish bought in bags (usually Clupeids).

Fish were stockpiled for one week by 46% or two weeks by 47% of the

primary sellers before marketing.

During this time, some of the fish suffered from mould and insect

infestation resulting in a loss of appr. 6% by weight of dried fish.

1 Fish burning usually followed by hot smoking in "banda" producesblack traditional product which was said to be firmer than normalsmoked fish although losses in the nutritive value was inevitablefrom the hurning process.

III

One active fisheries co-operative society (Fresh Fish Co-operative

Society) that is involved in buying and selling fish in distant

markets was found in Yauri. Another fisheries society (Sarikawa

Mabunta), also based in Yauri, is yet to take off. To get a better

picture of spoilage at the lower end of the marketing channel

Onitsha Osa fish market was visited. There, fish is sold directly

to retailers through commissioned agents. An estimated S% of fish

purchased from the secondary sellers suffered from fraamentation

and spoilage at the processing site. Incident of insect attack was

very minimal. This was attributed to the effect of the pesticide

"Otapiapia".

Considering the total catch from gillnets, longlines, traps

and cast nets estimated at 14,000t in 1995 about 1,000t of fish

was either discarded or lost value due to spoilage during handling

by fisherfolk. Assuming an average price of 80 Naira per kg of fish

the loss to the economy amounted to 80 million Naira yearly.

Appropriate recommendations have been made to significantly reduce

post-harvest losses in Kainji Lake fishery.

III

One active fisheries co-operative society (Fresh Fish Co-operative

Society) that is involved in buying and selling fish in distant

markets was found in Yauri. Another fisheries society (Sarikawa

Mabunta), also based in Yauri, is yet to take off. To get a better

picture of spoilage at the lower end of the marketing channel

Onitsha Osa fish market was visited. There, fish is sold directly

to retailers through commissioned agents. An estimated S% of fish

purchased from the secondary sellers suffered from fraamentation

and spoilage at the processing site. Incident of insect attack was

very minimal. This was attributed to the effect of the pesticide

"Otapiapia".

Considering the total catch from gillnets, longlines, traps

and cast nets estimated at 14,000t in 1995 about 1,000t of fish

was either discarded or lost value due to spoilage during handling

by fisherfolk. Assuming an average price of 80 Naira per kg of fish

the loss to the economy amounted to 80 million Naira yearly.

Appropriate recommendations have been made to significantly reduce

post-harvest losses in Kainji Lake fishery.

1

1. INTRODUCTION

Fish provides an excellent source of protein in the diet of

many homes the world over. The quality of fish protein is as good

as that of beet, milk, pork and poultry. Fish has an edge over

these protein sources in that it is more affordable and available

in rural as well as urban centres. There is also no religious taboo

influencing the consumption of fish as it does with pork, beef and

some game. Inspite of these merits fresh fish is one of the most

perishable foods. Fish spoil very quickly as a result of intrinsic

and extrinsic factors. The high ambient temperature hasten fish

snoilage by accelerating the activities of bacteria, enzymes and

chemical oxidation of fat in fish flesh. Unwholesome fish may be

discarded by fisherfolk at different stages of handling and

processing leading to economic and nutritional loss in the fishing

industry.

Post harvest losses occur at different points from capture to

marketing and in some fishery the level of losses could be

considerable. FAO (1981) has estimated post-harvest losses in

developing countries to be up to 50% of domestic fish production.

In Nigeria, post-harvest losses has been put at 50% (Dada and

Nnanados, 1983) and 30-50% (Tobor, 1984).

The demand for fish in Nigeria is estimated to be 1.18 million

tons (12 kg per capita) and the potential for Nigeria fish

resources is estimated at 1.83 million tons (Tobor 1993).

1

1. INTRODUCTION

Fish provides an excellent source of protein in the diet of

many homes the world over. The quality of fish protein is as good

as that of beet, milk, pork and poultry. Fish has an edge over

these protein sources in that it is more affordable and available

in rural as well as urban centres. There is also no religious taboo

influencing the consumption of fish as it does with pork, beef and

some game. Inspite of these merits fresh fish is one of the most

perishable foods. Fish spoil very quickly as a result of intrinsic

and extrinsic factors. The high ambient temperature hasten fish

snoilage by accelerating the activities of bacteria, enzymes and

chemical oxidation of fat in fish flesh. Unwholesome fish may be

discarded by fisherfolk at different stages of handling and

processing leading to economic and nutritional loss in the fishing

industry.

Post harvest losses occur at different points frcm capture to

marketing and in some fishery the level of losses could be

considerable. FAO (1981) has estimated post-harvest losses in

developing countries to be up to 50% of domestic fish production.

In Nigeria, post-harvest losses has been put at 50% (Dada and

Nnanados, 1983) and 30-50% (Tobor, 1984).

The demand for fish in Nigeria is estimated to be 1.18 million

tons (12 kg per capita) and the potential for Nigeria fish

resources is estimated at 1.83 million tons (Tobor 1993).

2

With fish supply estimated at less than 500,000 tons, meeting

the demand for fish is unattainable unless the production is

improved by more efficient fisheries management and development,

development of aquaculture and improvement in fish handling,

processing, storage and distribution.

Reducing post-harvest losses will increase availability of

fish protein, enhance the nutritional status of the people, reduce

fish importation and save the country's foreign exchange earnings.

2. TERMS OF REFERENCE

After a brief review of existing literature the expert in fish

processing shall:

describe and assess in detail the different fish processing

methods employed around Kainji Lake.

assess the amount of fish lost during fish handling and

processing.

estimate the post harvest losses that occur during marketing

process.

recommend how to reduce post harvest losses in Kainji Lake.

2

With fish supply estimated at less than 500,000 tons, meeting

the demand for fish is unattainable unless the production is

improved by more efficient fisheries management and development,

development of aquaculture and improvement in fish handling,

processing, storage and distribution.

Reducing post-harvest losses will increase availability of

fish protein, enhance the nutritional status of the people, reduce

fish importation and save the country's foreign exchange earnings.

2. TERMS OF REFERENCE

After a brief review of existing literature the expert in fish

processing shall:

describe and assess in detail the different fish processing

methods employed around Kainji Lake.

assess the amount of fish lost during fish handling and

processing.

estimate the post harvest losses that occur during marketing

process.

recommend how to reduce post harvest losses in Kainji Lake.

3

3. REVIEW OF LITERATURE

3.1 Fish DeteriorationImmediately the fish dies it remains in first class quality

for only a short while. Within this period, the flesh is firm and

tender, the skin is bright with firm scales. The gills are bright

red exuding fresh odour and the eyes are bulging or convex and

iridescent. After a few hours depending on the specie and the

prevailing ambient temperature the flesh begins to soften and later

become flabby, the skin looses its sheen with loose scales, the

gills change colour from bright red to pink and later greenish with

ammoniacal odour, the eyes become sunken in the cranium. The fish

has now lost its acceptability and is rejected by consumers as

unfit for human consumption.

Three main natural factors have been implicated in post

harvest losses. These are:

activities of micro-organisms,

chemical deterioration such as the breakdown of fats and

enzymatic activity; and

insect infestation.

Micro-organisms such as bacteria, mould and yeast are

responsible for putrefaction and the development of unsightly

appearance and toxic substances in the fish which may be passed to

consumers. Micro-organisms are often arrested by controlling

product water and or salt content, chemical treatments, temperature

reduction and by good sanitation and handling practices (Wheaton

and Lawson, 1985).

3

3. REVIEW OF LITERATURE

3.1 Fish DeteriorationImmediately the fish dies it remains in first class quality

for only a short while. Within this period, the flesh is firm and

tender, the skin is bright with firm scales. The gills are bright

red exuding fresh odour and the eyes are bulging or convex and

iridescent. After a few hours depending on the specie and the

prevailing ambient temperature the flesh begins to soften and later

become flabby, the skin looses its sheen with loose scales, the

gills change colour from bright red to pink and later greenish with

ammoniacal odour, the eyes become sunken in the cranium. The fish

has now lost its acceptability and is rejected by consumers as

unfit for human consumption.

Three main natural factors have been implicated in post

harvest losses. These are:

activities of micro-organisms,

chemical deterioration such as the breakdown of fats and

enzymatic activity; and

insect infestation.

Micro-organisms such as bacteria, mould and yeast are

responsible for putrefaction and the development of unsightly

appearance and toxic substances in the fish which may be passed to

consumers. Micro-organisms are often arrested by controlling

product water and or salt content, chemical treatments, temperature

reduction and by good sanitation and handling practices (Wheaton

and Lawson, 1985).

4

Chemical deterioration include che oxidation of fat that

causes rancid flavour, breakdown of the edible flesh by enzymes

(autolysis) with the production of off-odour and flavour and other

chemical reactions.

Insects such as blowflies and beetles attack fish at various

stages of handling, processing and storage causing losses of the

edible flesh. Blowflies may oviposit on fresh fish that have been

exposed and produce maggots which pupate and the emerging adults

may re-infect another batch of drying fish. Beetles may invade

dried fish during storage and feed extensively on fish fiesh.

Insect feeding activity may cause ub to 5096- loss in weight of dried

fish in storage.

Vermin such as rats, dogs, chicken, cats, mites etc. also

scavenges on the fish and fish products.

The sooner any preservative measures are taken after capture,

the greater the chances of reducing post harvest losses in fish and

fish products.

3.2 Categories of Post Harvest Losses

Post harvest losses occur due to bad handling and preservation

methods and can be categorised as follows:

Physical losses:

This refers to losses of fish either completely (gross physical

losses) or by loss of some pieces (net physical losses).

Gross physical losses occur from dumping of low value by-catch at

sea (Bostock, 1987).

4

Chemical deterioration include the oxidation of fat that

causes rancid flavour, breakdown of the edible flesh by enzymes

(autolysis) with the production of off-odour and flavour and other

chemical reactions.

Insects such as blowflies and beetles attack fish at various

stages of handling, processing and storage causing losses of the

edible flesh. Blowflies may oviposit on fresh fish that have been

exposed and produce maggots which pupate and the emerging adults

may re-infect another batch of drying fish. Beetles may invade

dried fish during storage and feed extensively on fish flesh.

Insect feeding activity may cause up to 5096- loss in weight of dried

fish in storage.

Vermin such as rats, dogs, chicken, cats, mites etc. also

scavenges on the fish and fish products.

The sooner any preservative measures are taken after capture,

the greater the chances of reducing post harvest losses in fish and

fish products.

3.2 Categories of Post Harvest Losses

Post harvest losses occur due to bad handling and preservation

methods and can be categorised as follows:

Physical losses:

This refers to losses of fish either completely (gross physical

losses) or by loss of some pieces (net physical losses).

Gross physical losses occur from dumping of low value by-catch at

sea (Bostock, 1987).

5

This seldom happens in the artisanal fishery where most of the by-

catches are utilised. Whole spoilt fish which are uneatable and

have to be thrown away also fall into this category.

Net physical losses occur as a result of nutrient loss through

poor handling and processing. This includes dried fish in which

much of the flesh has been consumed by maggots or beetles in

storage, and fragmented fish which fall into the fire and cannot be

retrieved during smoking.

Economic losses:

Economic loss occurs due to downgrading of spoilt fish originally

meant for human consumption into fish meal. Usually partial

spoilage may not affect the value of the fish but as spoilage

increases the value drops. High quality fish which should have been

exported but downgraded for domestic consumption also fall into

this group.

Nutritional losses:

Nutritional loss is described as the loss of nutritional value of

fish due to spoilage or exposure to high temperature during smoking

causing damage to part of the protein fraction such as lysine.

3.3 Fish Handling Practices and their Implications for FishSpoilage

Handling means taking care of the catch from the time the fish

are hauled up until they are sold to the consumer either fresh,

preserved or processed.

5

This seldom happens in the artisanal fishery where most of the by-

catches are utilised. Whole spoilt fish which are uneatable and

have to be thrown away also fall into this category.

Net physical losses occur as a result of nutrient loss through

poor handling and processing. This includes dried fish in which

much of the flesh has been consumed by maggots or beetles in

storage, and fragmented fish which fall into the fire and cannot be

retrieved during smoking.

Economic losses:

Economic loss occurs due to downgrading of spoilt fish originally

meant for human consumption into fish meal. Usually partial

spoilage may not affect the value of the fish but as spoilage

increases the value drops. High quality fish which should have been

exported but downgraded for domestic consumption also fall into

this group.

Nutritional losses:

Nutritional loss is described as the loss of nutritional value of

fish due to spoilage or exposure to high temperature during smoking

causing damage to part of the protein fraction such as lysine.

3.3 Fish Handling Practices and their Implications for FishSpoilage

Handling means taking care of the catch from the time the fish

are hauled up until they are sold to the consumer either fresh,

preserved or processed.

6

Very often there is delay from the time fish are entangled in

the net up till when they are landed on deck. Some fish may die

inside the net long before they are removed. Such catches stand the

risk of spoilage at the time of harvesting.

Fish being removed from gears are often wrongly handled.

Captured fishes are thrown carelessly into the canoe, where they

lie in a pool of warm dirty water in the canoe bottom under the

prevailing high temperature (Mayboom, 1974; Eyo, 1977a).

When thrown about or trampled, some of the fish may be bruised

paving way for bacteria to enter the flesh and enhance spoilage.

Since the gut content is usually not removed bacteria lining

the viscera start invading the tissues. Removal of the viscera

eliminates the potential contamination of the edible flesh with

digestive enzymes. It prevents inoculation of fish flesh by micro-

organisms present in the intestinal tract and eliminates the gall

bladder which contains bile, an alkaline greenish liquid which can

cause a visible discoloration referred to as "belly burn" that

gives fish a bitter flavour (Regenstein and Regenstein, 1991).

Fish caught alive often struggle and die of asphyxia in the

dirty water inside the fishing vessel (Eyo, 1977a). Struggling

before death reduces the duration of rigor mortis (Annex 1) and

shortens the keeping time of the fish.

Generally small fish at the high ambient temperature will

enter and pass through rigor mortis very quickly, whereas large

fish that did not struggle before it dies will take a much longer

time to enter and pass through rigor.

6

Very often there is delay from the time fish are entangled in

the net up till when they are landed on deck. Some fish may die

inside the net long before they are removed. Such catches stand the

risk of spoilage at the time of harvesting.

Fish being removed from gears are often wrongly handled.

Captured fishes are thrown carelessly into the canoe, where they

lie in a pool of warm dirty water in the canoe bottom under the

prevailing high temperature (Maybocm, 1974; Eyo, 1977a).

When thrown about or trampled, some of the fish may be bruised

paving way for bacteria to enter the flesh and enhance spoilage.

Since the gut content is usually not removed bacteria lining

the viscera start invading the tissues. Removal of the viscera

eliminates the potential contamination of the edible flesh with

digestive enzymes. It prevents inoculation of fish flesh by micro-

organisms present in the intestinal tract and eliminates the gall

bladder which contains bile, an alkaline greenish liquid which can

cause a visible discoloration referred to as "belly burn" that

gives fish a bitter flavour (Regenstein and Regenstein, 1991).

Fish caught alive often struggle and die of asphyxia in the

dirty water inside the fishing vessel (Eyo, 1977a). Struggling

before death reduces the duration of rigor mortis (Annex 1) and

shortens the keeping time of the fish.

Generally small fish at the high ambient temperature will

enter and pass through rigor mortis very quickly, whereas large

fish that did not struggle before it dies will take a much longer

time to enter and pass through rigor.

7

To consider the phenomenon of rigor mortis is important in the

handling of fresh fish because bacterial spoilage of fish does not

begin until the passage of rigor mortis when juices are released

from the muscle fibres (Wheaton and Lawson, 1985). Any delay

therefore in the onset of rigor or in its duration will prolong the

keeping time of the fish. Since the warmer the fish the sooner it

will go into and pass through rigor (Stroud, 1969), ice or

refrigeration has been used effectively in reducing fish

temperature, slowing down bacteria/spoilage and therefore improvina

the keeping time of the fish.

3.4 Fish Preservation/Processing

Fish processing has the following functions: (1) preservation

of the product, (2) converting the raw material to a desirable

form, (3) maintaining oroduct auality, (4) assuring consumer's

safety, and (5) full utilisation of the raw material (Wheatson and

Lawson, 1985).

Usually, the market for fresh fish are a long distance away

from the fishing areas. The high temperatures prevailing cause

rapid deterioration of the fish. Fish preservation is therefore a

crucial aspect of fisheries commerce and needs adequate attention.

The commonest preservation methods are smoking, salting, sun

drying, icing, freezing and cold storage.

7

To consider the phenomenon of rigor mortis is important in the

handling of fresh fish because bacterial spoilage of fish does not

begin until the passage of rigor mortis when juices are released

from the muscle fibres (Wheaton and Lawson, 1985). Any delay

therefore in the onset of rigor or in its duration will prolong the

keeping time of the fish. Since the warmer the fish the sooner it

will go into and pass through rigor (Stroud, 1969), ice or

refrigeration has been used effectively in reducing fish

temperature, slowing down bacteria/spoilaae and therefore improvina

the keeping time of the fish.

3.4 Fish Preservation/Processing

Fish processing has the following functions: (1) preservation

of the product, (2) converting the raw material to a desirable

form, (3) maintaining product auality, (4) assuring consumer's

safety, and (5) full utilisation of the raw material (Wheatson and.

Lawson, 1985).

Usually, the market for fresh fish are a long distance away

from the fishing areas. The high temperatures prevailing cause

rapid deterioration of the fish. Fish preservation is therefore a

crucial aspect of fisheries commerce and needs adequate attention.

The commonest preservation methods are smoking, salting, sun

drying, icing, freezing and cold storage.

2

8

3.4.1 Fish Smoking

Two main types of smoking processes are used in fish smoking:

hot and cold smoking 2. In Nigeria hot smoking is the major

traditional preservation method comprising 60-6596 of the total fish

landing in inland waters (Eyo, 1992a). The main aim of traditional

smoking is to preserve the catch although additional benefits such

as improvement in the flavour of smoked fish is achieved. Fish

smoking is done with wood. Wood smoke is a complex mixture of

several hundred reactive compounds which are produced by the

pyrolysis of wood followed by further chemical interactions between

initial products of pyrolysis (Toth, 1982). The preservation effect

of the smoking process is primarily due to the drying of the fish

during smoking, by the absorption of chemical compounds in the

smoke by fish flesh and the deposition of some antimicrobial

chemicals in the smoke that remain on the fish.

Furthermore, when the temperature is high enough, readhing

120°C or so, the fish will be cooked preventing bacterial growth

and enzyme activity.

In the cold smoking process the temperature of the smokedoes not exceed 30 C. The shelf-life of the cola smokedfish is usually shorter than in hot smoking. Cold smokingtechniques do not preserve the fish but are merely cosmeticto produce a smoking flavour except when carried out for a longtime, usually several weeks.

2

8

3.4.1 Fish Smoking

Two main types of smoking processes are used in fish smoking:

hot and cold smoking 2 In Nigeria hot smoking is the major

traditional preservation method comprising 60-6596 of the total fish

landing in inland waters (Eyo, 1992a). The main aim of traditional

smoking is to preserve the catch although additional benefits such

as improvement in the flavour of smoked fish is achieved. Fish

smoking is done with wood. Wood smoke is a complex mixture of

several hundred reactive compounds which are produced by the

pyrolysis of wood followed by further chemical interactions between

initial products of pyrolysis (Toth, 1982). The preservation effect

of the smoking process is primarily due to the drying of the fish

during smoking, by the absorption of chemical compounds in the

smoke by fish flesh and the deposition of some antimicrobial

chemicals in the smoke that remain on the fish.

Furthermore, when the temperature is high enough, readhing

120°C or so, the fish will be cooked preventing bacterial growth

and enzyme activity.

In the cold smoking process the temperature of the smokedoes not exceed 30 C. The shelf-life of the cola smokedfish is usually shorter than in hot smoking. Cold smokingtechniques do not preserve the fish but are merely cosmeticco produce a smoking flavour except when carried cut for a longtime, usually several weeks.

9

Factors affecting wood-smoke composition and absorption

include the type of wood, the moisture content of the wood, te

wood combustion temperature, the smoke house humidity and air flow

(Clifford, Tang and Eyo, 1980).

Studies conducted to verify the effect of nine woods used for

fish smoking in Kainji lake area showed that Deterium microcarpum

(Taura), Parkia clappertoniania (Dorawa), and Danielli oliveri

(Maje) imparted the best colour and flavour to smoked fish.

Crossopteryx februfuaa (Kasfiya Rashin Asaki) imparted good colour

but poor flavour whilst Pterocarpus angolensis (Kolo) produced dark

brown colour and good flavour.

The products smoked by Butyrospermum paradoxum (Kadanya),

Gardenia sokolensis (Ganden-Dutse) and Afzelia africana (Kawo) were

unacceptable (Eyo, 1985).

Types of smokina kilns

The smoking kilns used in Nigeria vary ranging from the

simple pit type to the drum or mud walled type which may be

circular or rectangular in shaoe. The pit type ovens expose the

fish to burning since there is often considerable difficulty in

controlling the extent of fire in the pit.

The commonest smoking kiln in Nigeria is the" Banda" type

which may be constructed with mud or empty oil drum. The kiln

consist o racks raised on poles or racks placed on top of a

rectangular or circular mud or flattened drum base with openings

for the fire. Fish are either placed whole or cut into chunks.

9

Factors affecting wood-smoke composition and absorption

include the type of wood, the moisture content of the wood, the

wood combustion temperature, the smoke house humidity and air flow

(Clifford, Tang and Eye, 1980).

Studies conducted to verify the effect of nine woods used for

fish smoking in Kainji lake area showed that Deterium microcarpum

(Taura), Parkia clappertoniania (Dorawa), and Daniell' oliveri

(Maje) imparted the best colour and flavour to smoked fish.

Crossopteryx februfuaa (Kasfiya Rashin Asaki) imparted good colour

but poor flavour whilst Pterocarpus angolensis (Kole) produced dark

brown colour and good flavour.

The products smoked by Butyrospermum paradoxum (Kadanya),

Gardenia sokolensis (Ganden-Dutse) and Afzelia africana (Kawo) were

unacceptable (Eyo, 1985).

Types of smoking kilns

The smoking kilns used in Nigeria vary ranging from the

simple pit type to the drum or mud walled type which may be

circular or rectangular in shaPe. The pit type ovens expose the

fish to burning since there is often considerable difficulty in

controlling the extent of fire in the pit.

The commonest smoking kiln in Nigeria is the" Banda" type

which may be constructed with mud or empty oil drum. The kiln

consist of racks raised on poles or racks placed on top of a

rectangular or circular mud or flattened drum base with openings

for the fire. Fish are either placed whole or cut into chunks.

10

Whole fish may be skewered into a pointed stick or into the fish

own pectoral spine before they are laid on the rack (Eyo, 1977a).

The fish may or may not be salted and some may be dressed and

gutted before they are smoked. Smoke is supplied by wood or burning

grass. The longer the fish is smoked, the drier it becomes and

close supervision is essential to ensure that the fish are not

charred during the smoking process.

The traditional smoking kiln has the advantage of being of low

capital cost. The disadvantages have been reported by Clucas (1982)

as follows:

Constant attention is required to control the fire and turn

the fish. This may involve working throughout the night.

The operation is both a health and fire hazard.

Many ovens are inefficient in their use of fuel and

ventilation system.

There is little or no control over the temperature of the

fire and the density of the smoke produced.

The construction materials used limit the durability of the

ovens.

The open construction of the ovens leave the fish

susceptible to climatic conditions and animal attack.

The fish product is of poor quality due to insufficient

cooking of flesh inside and burning and charring of the

outside.

Other smoking kilns which have been tested in Nigeria inland

fisheries with variable results are the following:

10

Whole fish may be skewered into a pointed stick or into the fish

own pectoral spine before they are laid on the rack (Eyo, 1977a).

The fish may or may not be salted and some may be dressed and

gutted before they are smoked. Smoke is supplied by wood or burning

grass. The longer the fish is smoked, the drier it becomes and

close supervision is essential to ensure that the fish are not

charred during the smoking process.

The traditional smoking kiln has the advantage of being of low

capital cost. The disadvantages have been reported by Clucas (1982)

as follows:

Constant attention is required to control the fire and turn

the fish. This may involve working throughout the night.

The operation is both a health and fire hazard.

Many ovens are inefficient in their use of fuel and

ventilation system.

There is little or no control over the temperature of the

fire and the density of the smoke produced.

The construction materials used limit the durability of the

ovens.

The open construction of the ovens leave the fish

susceptible to climatic conditions and animal attack.

The fish product is of poor quality due to insufficient

cooking of flesh inside and burning and charring of the

outside.

Other smoking kilns which have been tested in Nigeria inland

fisheries with variable results are the following:

11

Modified Altona or Watanabe Smoking Kiln (WSKJ

An improved traditional kiln with a remote fire box that can

be constructed with mud bricks or cement blocks. The kiln dimension

is variable but typically it is 1.5 x 1.25 x 3.65m and is connected

by a 1.5m asbestos pipe of 350mm diameter to a firebox of dimension

0.8 x 0.5 x 1.0m. The kiln has 3 evenly spaced wire mesh trays and

could smoke up to SOkg of fresh fish at a time. The duration of

smoking depends on the heat supplied and may last for 24 hours or

more.

Altona Smoking Kiln (ASK)

As above without the connection to a fire-box. The smoking

chamber has a metal door and the firing compartment has a stoke

hole.

Chorkor Oven

A Chorkor Oven is a rectangular mud or brick oven with trays.

It is about 70cm wide, 70cm long and 70cm high. Wall thi kness is

I5cm. Smoking trays are about 80cm x 80cm x 7cm and storage trays

are 80cm x 80cm x 12cm. Rounding off and tapering the inside

corners improves heat and smoke distribution, The Chorkor Oven

saves fuel wood since it operates up to 5 smoking trays that are

stacked to form a chimney at the same time. Trays are rotated

during the smoking process. For storage up to 15 storage trays may

be stacked over an oven and covered with plastic sheeting.

11

Modified Altona or Watanabe Smoking Kiln (WSK)

An improved traditional kiln with a remote fire box that can

be constructed with mud bricks or cement blocks. The kiln dimension

is variable but typically it is 1.5 x 1.25 x 3.65m and is connected

by a 1.5m asbestos pipe of 350mm diameter to a firebox of dimension

0.8 x 0.5 x 1.0m. The kiln has 3 evenly spaced wire mesh trays and

could smoke up to 50kg of fresh fish at a time. The duration of

smoking depends on the heat supplied and may last for 24 hours or

more.

Altona Smoking Kiln (ASK)

As above without the connection to a fire-box. The smoking

chamber has a metal door and the firing compartment has a stoke

hole.

Chorkor Oven

A Chorkor Oven is a rectangular mud or brick oven with trays.

It is about 70cm wide, 70cm long and 70cm high. Wall thickness is

15cm. Smoking trays are about 80cm x 80cm x 7cm and storage trays

are 80cm x 80cm x 12cm. Rounding off and tapering the inside

corners improves heat and smoke distribution. The Chorkor Oven

saves fuel wood since it operates up to 5 smoking trays that are

stacked to form a chimney at the same time. Trays are rotated

during the smoking process. For storage up to 15 storage trays may

be stacked over an oven and covered with plastic sheeting.

12

From time to time the sheeting is removed to re-smoke (re-heat and

re-dry) the fish. Often two ovens are built together and trays are

made to cover both ovens. Chorkor Smokers have been found by Dampha

(1993) to have the following advantages:

Low construction cost depending on the availability of

framing boards and wire mesh;

Long life and low maintenance if protected from rain;

Large capacity depending on the availability of fish and the

number of trays used during smoking;

High quality and uniformity of product;

Easy to operate;

Easily adoptable since in keeping with the smoking habits of

most traditional women;

No smoke in the eyes;

Greatly reduced consumption of fuel wood.

(iii) Kainji Gas Kiln (KGK)

The kiln was invented by the author (Eyo, 1981) and patented

by the National Institute for Freshwater Fisheries Research

(NIFFR), New Bussa. It has a structural framework of angle bars and

hollow pipes with dimension 0.92 x 0.76 x 1.24cm.

The smoking chamber has dimension 0.66 x 0.76 x 0.94m and

adjacent to the chamber are chests of drawers where sawdust and

wood shavings are burnt. Below the smoking chamber is the furnace

and here burning butane gas generates heat into the smoking

chamber.

12

From time to time the sheeting is removed to re-smoke (re-heat and

re-dry) the fish. Often two ovens are built together and trays are

made to cover both ovens. Chorkor Smokers have been found by Dampha

(1993) to have the following advantages:

Low construction cost depending on the availability of

framing boards and wire mesh;

Long life and low maintenance if protected from rain;

Large capacity depending on the availability of fish and the

number of trays used during smoking;

High quality and uniformity of product;

Easy to operate;

Easily adoptable since in keeping with the smoking habits of

most traditional women;

No smoke in the eyes;

Greatly reduced consumption of fuel wood.

(iii) Kainji Gas Kiln (KGK)

The kiln was invented by the author (Eyo, 1981) and patented

by the National Institute for Freshwater Fisheries Research

(NIFFR), New Bussa. It has a structural framework of angle bars and

hollow pipes with dimension 0.92 x 0.76 x 1.24cm.

The smoking chamber has dimension 0.66 x 0.76 x 0.94m and

adjacent to the chamber are chests of drawers where sawdust and

wood shavings are burnt. Below the smoking chamber is the furnace

and here burning butane gas generates heat into the smoking

chamber.

13

The entire framework is covered with steel plates which is

perforated at the top with a pipe connection to form a chimney.

Fish is placed on 5 or more wire mesh trays inside the smoking

chamber through openings in the drawers.

The combination of smoke from wood shavings and heat from burning

butane gas produces smoked fish that are more attractive than those

smoked traditionally.

A comparison of the performance of the KGK with other commonly

used smoking kilns (Eyo, 1993a) shows that fish smoked with the KGK

had the best taste, flavour, appearance and overall acceptability

followed by those smoked with the Watanabe kiln.

The quality of fish smoked with the ASK was still better than

those smoked with the traditional kiln (TSK). The better quality of

fish smoked with the KGK and the WSK was attributed to the

generation of the smoke externally which prevented contamination of

the smoked fish with tar, soot and other smoke particles from the

burning sawdust and wood respectively.

Other merits of the Kainji Gas Kiln are as follows:

_ Fish is completely smoked in six hours;

The smoking process is under the control of the operator;

- The smoked fish from the Kainji Gas Kiln is more hygienic;

_ The method is less labour intensive and does not require

many operators;

- Because smoke is generated externally, smoked fish from the

KGK will contain less polycyclic aromatic hydrocarbons (PAR)

than those smoked traditionally.

13

The entire framework is covered with steel plates which is

perforated at the top with a pipe connection to form a chimney.

Fish is placed on 5 or more wire mesh trays inside the smoking

chamber through openings in the drawers.

The combination of smoke from wood shavings and heat from burning

butane gas produces smoked fish that are more attractive than those

smoked traditionally.

A comparison of the performance of the KGK with other commonly

used smoking kilns (Eyo, 1993a) shows that fish smoked with the KGK

had the best taste, flavour, appearance and overall acceptability

followed by those smoked with the Watanabe kiln.

The quality of fish smoked with the ASK was still better than

those smoked with the traditional kiln (TSK). The better quality of

fish smoked with the KGK and the WSK was attributed to the

generation of the smoke externally which prevented contamination of

the smoked fish with tar, soot and other smoke particles from the

burning sawdust and wood respectively.

Other merits of the Kainji Gas Kiln are as follows:

_ Fish is completely smoked in six hours;

The smoking process is under the control of the operator;

- The smoked fish from the Kainji Gas Kiln is more hygienic;

_ The method is less labour intensive and does not require

many operators;

- Because smoke is generated externally, smoked fish from the

KGK will contain less polycyclic aromatic hydrocarbons (PAR)

than those smoked traditionally.

14

The smoked fish from the KGK have attractive colour and

savoury flavour;

The equipment is portable and can be operated in a large

enough fishing boat so that catching and preservation could

be done simultaneously;

Since smoke is produced by sawdust and wood shavings,

incidents of deforestation for fish smoking is reduced.

The cost of operation of the kiln is quite moderate. Wood

shavings and sawdust do not cost anything and a 12.5kg gas

cylinder costing Naira 150 - 250 can complete three batches

of smoking successfully.

However since the kiln is made of mildsteel and other

mechanical devices, the initial cost of purchase may be high.

3.4.2 Fish Drying

Principles of drying

Drying means the removal of moisture from a product. This may

be carried out by evaporation of water, application of pressure,

addition of salt or by using absorbent pads (Wheatson and Lawson

(1987). For fish preservation, the commonest method used is

evaporation/dehydration.

There are two stages in the fish drying process: 1) removing

the surface moisture, and 2) removing the internal moisture within

the fish.

14

The smoked fish from the KGK have attractive colour and

savoury flavour;

The equipment is portable and can be operated in a large

enough fishing boat so that catching and preservation could

be done simultaneously;

Since smoke is produced by sawdust and wood shavings,

incidents of deforestation for fish smoking is reduced.

The cost of operation of the kiln is quite moderate. Wood

shavings and sawdust do not cost anything and a 12.5kg gas

cylinder costing Naira 150 - 250 can complete three batches

of smoking successfully.

However since the kiln is made of mildsteel and other

mechanical devices, the initial cost of purchase may be high.

3.4.2 Fish Drying

Principles of drying

Drying means the removal of moisture from a product. This may

be carried out by evaporation of water, application of pressure,

addition of salt or by using absorbent pads (Wheatson and Lawson

(1987). For fish preservation, the commonest method used is

evaporation/dehydration.

There are two stages in the fish drying process: 1) removing

the surface moisture, and 2) removing the internal moisture within

the fish.

15

The drying rate in the first stage depends on ability of air

passing over the fish to absorb or remove moisture thus on the air

speed and Relative Humidity (RH). High outside temperature and

increasing the surface of the fish by opening it up hastens the

drying process.

The duration of the second drying stage is determined by the

rate at which moisture can migrate through the tissue to the

surface of the fish. The rate of movement of water within the fish

depends on factors such as:

fat content of the fish (fat acts as a barrier to water

movement and slows down the drying rate).

thickness of the fish (the thinner the fish the faster the

drying rate).

moisture content (movement of the water to the surface

becomes more difficult when the fish becomes dry and the fat

content becomes higher).

If during the early drying stage the fish is dried at too high

a temperature (more than 40 C) or when the RH is too low, the outer

layers become 'cooked' or altered so as to be almost impervious to

water. This effect is known as 'case hardening'.

The fish may appear dried but water becomes trapped inside

leading to insufficient drying and early spoilage.

Sun drying and salting

Sun drying in Nigeria is practiced mainly in the Sahel zone

with its high level of solar energy.

15

The drying rate in the first stage depends on ability of air

passing over the fish to absorb or remove moisture thus on the air

speed and Relative Humidity (RH). High outside temperature and

increasing the surface of the fish by opening it up hastens the

drying process.

The duration of the second drying stage is determined by the

rate at which moisture can migrate through the tissue to the

surface of the fish. The rate of movement of water within the fish

depends on factors such as:

fat content of the fish (fat acts as a barrier to water

movement and slows down the drying rate).

thickness of the fish (the thinner the fish the faster the

drying rate).

moisture content (movement of the water to the surface

becomes more difficult when the fish becomes dry and the fat

content becomes higher).

If during the early drying stage the fish is dried at too high

a temperature (more than 40 C) or when the RH is too low, the outer

layers become 'cooked' or altered so as to be almost impervious to

water. This effect is known as 'case hardening'.

The fish may appear dried but water becomes trapped inside

leading to insufficient drying and early spoilage.

Sun drying and salting

Sun drying in Nigeria is practiced mainly in the Sahel zone

with its high level of solar energy.

16

Traditionally, small fish like clupeids are displayed on

plastic sheets on the ground in the open and dried within a day.

Fish of considerable size are cut into chunks and allowed to dry in

the hot sun. Dry leaves, grasses and mats are placed over the dried

fish and burnt. The charred fish are again sun dried before they

are packed and sold out. In some cases, fish are split

longitudinally from head to tail and hung on racks to dry. The

drying period is 4 to 7 days depending on the intensity of sunlight

(Azeza, 1980).

Dry salting and kench salting improves the quality of the

product. When dry salted the fish are filleted and granular salt is

rubbed into the surface after which the fish are hung to dry. In

kench salting the granular salt is rubbed into the fillets which

are then stacked on a layer of salt. The processing period may last

for three days.

The dry salting method is being used of recent in the

processing of small sardines or clupeids (Eyo, 1992b). The fish is

"roused" in a small quantity of salt before being placed on racks

to dry in the sun.

Raised drying racks offer improved air flow, allow moisture to

drain away, and protect the product from rain and from water on the

ground.

As a general guideline, if no salt is used the weight of

properly dried fish is between 25% (lean fish) and 35% (fatty fish)

of its raw weight. The weight of salted dried fish is ideally

between 45% (lean fish) and 55% (fatty fish) of the raw weight.

16

Traditionally, small fish like clupeids are displayed on

plastic sheets on the ground in the open and dried within a day.

Fish of considerable size are cut into chunks and allowed to dry in

the hot sun. Dry leaves, grasses and mats are placed over the dried

fish and burnt. The charred fish are again sun dried before they

are packed and sold out. In some cases, fish are split

longitudinally from head to tail and hung on racks to dry. The

drying period is 4 to 7 days depending on the intensity of sunlight

(Azeza, 1980).

Dry salting and kench salting improves the quality of the

product. When dry salted the fish are filleted and granular salt is

rubbed into the surface after which the fish are hung to dry. In

kench salting the granular salt is rubbed into the fillets which

are then stacked on a layer of salt. The processing period may last

for three days.

The dry salting method is being used of recent in the

processing of small sardines or clupeids (Eyo, 1992b). The fish is

"roused" in a small quantity of salt before being placed on racks

to dry in the sun.

Raised drying racks offer improved air flow, allow moisture to

drain away, and protect the product from rain and from water on the

ground.

As a general guideline, if no salt is used the weight of

properly dried fish is between 25% (lean fish) and 35% (fatty fish)

of its raw weight. The weight of salted dried fish is ideally

between 45% (lean fish) and 55% (fatty fish) of the raw weight.

17

Solar drying

Solar dryers whether made of plastic or glass generally have

a lower drying rate in the first phase of drying when the high

humidity in the drier retards the removal of water. In the second

phase a higher drying rate is obtained because of the higher

temperature and lower humidity in a solar drier in this phase. In

balance solar drying shows a slight time gain (in the order of 10%)

as against to drying in the outside air. Furthermore a cleaner

product is obtained in a solar dryer.

If temperatures in excess of 45°C are attained inside solar

dryers insects and their larvae get killed; at temperatures over

60°C also the eggs of the insects are killed. However, temperature

has to be controlled in the first drying phase to avoid cooking of

the fish resulting in low product quality.

The present type of solar dryers available do not support

intensive commercial use because of their low capacity and

durability. Also, the construction material may not easily be found

locally.

3.4.3 Icing

Icing of fish is one of the best methods of reducing fish

spoilage. However it is essential that the right quantity of ice be

used to chill a known quantity of fish. This can easily be

calculated if the specific heat of the fish is known.

17

Solar drying

Solar dryers whether made of plastic or glass generally have

a lower drying rate in the first phase of drying when the high

humidity in the drier retards the removal of water. In the second

phase a higher drying rate is obtained because of the higher

temperature and lower humidity in a solar drier in this phase. In

balance solar drying shows a slight time gain (in the order of 109()

as against to drying in the outside air. Furthermore a cleaner

product is obtained in a solar dryer.

If temperatures in excess of 45°C are attained inside solar

dryers insects and their larvae get killed; at temperatures over

6000 also the eggs of the insects are killed. However, temperature

has to be controlled in the first drying phase to avoid cooking of

the fish resulting in low product quality.

The present type of solar dryers available do not support

intensive commercial use because of their low capacity and

durability. Also, the construction material may not easily be found

locally.

3.4.3 Icing

Icing of fish is one of the best methods of reducing fish

spoilage. However it is essential that the right quantity of ice be

used to chill a known quantity of fish. This can easily be

calculated if the specific heat of the fish is known.

18

Example:

Amount of fish: 50kg

Specific heat of fish: 1 Kcal/kg

Specific heat of ice: 80 Kcal/kg

Temperature target: from 30°C to 0°C.

Amount of ice needed: (50 * 30) 1,500kg

1,500kg/80 = 18.75kg

The actual requirement of ice may be slightly higher (10)

especially in the high tropical temperature due to heat leaks

during transportation of ice.

It is generally recommended to have at least one part of ice

to three parts of fish by weight. Even if the right quantity of ice

is used, some fish may spoil if they are not completely surrounded

by ice.

Spoilage may also occur if the fish transport boxes do not

provide for escape of melting water or if the drained melt water is

allowed to re-contaminate the fish below when the boxes are

stacked.

Wooden ice boxes made from plywood dimension 60cm x 40cm x

20cm have been found to be convenient in transporting wet fish in

ice.

Using ice boxes it has been reported that tilapia and catfish

will remain edible for 25 to 30 days and 16 to 20 days respectively

if buried in ice. Even better results are obtained if the fish are

gutted and wrapped (Eyo, 1993b).

18

Example:

Amount of fish: 50kg

Specific heat of fish: 1 Kcal/kg

Specific heat of ice: 80 Kcal/kg

Temperature target: from 30°C to 0°C.

Amount of ice needed: (50 * 30) 1,500kg

1,500kg/80 = 18.75kg

The actual requirement of ice may be slightly higher (109(,)

especially in the high tropical temperature due to heat leaks

during transportation of ice.

It is generally recommended to have at least one part of ice

to three parts of fish by weight. Even if the right quantity of ice

is used, some fish may spoil if they are not completely surrounded

by ice.

Spoilage may also occur if the fish transport boxes do not

provide for escape of melting water or if the drained melt water is

allowed to re-contaminate the fish below when the boxes are

stacked.

Wooden ice boxes made from plywood dimension 60cm x 40cm x

20cm have been found to be convenient in transporting wet fish in

ice.

Using ice boxes it has been reported that tilapia and catfish

will remain edible for 25 to 30 days and 16 to 20 days respectively

if buried in ice. Even better results are obtained if the fish are

gutted and wrapped (Eyo, 1993b).

19

In Africa, this type of fish preservation is hardly used in

the artisanal inland fishery.

Experiments have shown that in the absence of ice, fish kept

in the shed had a much longer keeping time than those left in water

or exposed to direct sunlight (Eyo, 1977b).

3.4.4 Freezing

The commonest eauipment for freezing fish and also for lona

term storage of frozen fish is the cabinet (deep) freezer that is

used especially by small scale fisheries investors.

Fish may spoil in the freezers due to poor handling of the

equipment for the following reasons:

- equipment is frequently opened resulting in temperature

fluctuation that may lead to dehydration, alteration of the

protein and toughening of the product when thawed, and

- overloading of the freezers resulting in slow freezing of the

product, especially the bigger fish.

Imnroved freezers (that are only available in some fish

processing centres such as Nigerian National Shrimp Co. Ltd. Sanele

Delta State) are the air blast and plate freezers.

The air blast freezer is basically a tunnel in which a

cont nuous stream of air at -30°C is blown over the product. The

nlate freezer involves direct contact between the fish and

refrigerated metal plates with the refrigerant at -40°C.

19

In Africa, this type of fish preservation is hardly used in

the artisanal inland fishery.

Experiments have shown that in the absence of ice, fish kept

in the shed had a much longer keeping time than those left in water

or exposed to direct sunlight (Eyo, 1977b).

3.4.4 Freezing

The commonest eauipment for freezing fish and also for lona

term storaae of frozen fish is the cabinet (deep) freezer that is

used especially by small scale fisheries investors.

Fish may spoil in the freezers due to poor handling of the

equipment for the following reasons:

- equipment is frequently opened resulting in temperature

fluctuation that may lead to dehydration, alteration of the

protein and toughening of the product when thawed, and

- overloadina of the freezers resulting in slow freezing of the

product, especially the bigger fish.

Improved freezers (that are only available in some fish

processing centres such as Nigerian National Shrimp Co. Ltd. Sanele

Delta State) are the air blast and plate freezers.

The air blast freezer is basically a tunnel in which a

cont nuous stream of air at -30°C is blown over the product. The

plate freezer involves direct contact between the fish and

refrigerated metal plates with the refrigerant at -40°C.

20

3.4.5 Cold Stores

Fish processed in cold storages are usually kept there for

many weeks before they are removed. Often especially fish of

considerable size show signs of incipient spoilage on thawing.

The fish anpear wrinkled, toughened and whitish spots emerge on the

surfaces of the fish.

Those that are still wholesome become dry and hard, and crack

easily paving way for oxygen to penetrate into the flesh thereby

accelerating rancidity in fatty fish.

This condition is known as "freezer burn" and occurs whenever

fish is stored unprotected in condi ions of large temperature

differences between the fish and cooling coils.

Wrapping of the product or glazing regularly (by spraying or

dipping the frozen fish in water for a few seconds to leave a thin

skin of ice on the surface) reduces the problem.

Temperature fluctuation in the cold store can be avoided (i)

by provision of dunnage or palates to keep produce off the floor to

allow free air circulation, (ii) by ensuring that only one door is

open at a time and air locks are provided to reduce the heat load

in the cold store, (iii) by removing of produce in the store in the

same order that they were placed, (iv) by applying the principle

that fish should be frozen first in the deep freezer before stored

in the cold room, and (v) monitoring the samples in the store as

well as the cold store temperature at regular intervals.

20

3.4.5 Cold Stores

Fish processed in cold storages are usually kept there for

many weeks before they are removed. Often especially fish of

considerable size show signs of incipient spoilage on thawing.

The fish anpear wrinkled, toughened and whitish spots emerge on the

surfaces of the fish.

Those that are still wholesome become dry and hard, and crack

easily paving way for oxygen to penetrate into the flesh thereby

accelerating rancidity in fatty fish.

This condition is known as "freezer burn" and occurs whenever

fish is stored unprotected in condi ions of large temperature

differences between the fish and cooling coils.

Wrapping of the product or glazing regularly (by spraying or

dipping the frozen fish in water for a few seconds to leave a thin

skin of ice on the surface) reduces the problem.

Temperature fluctuation in the cold store can be avoided (i)

by provision of dunnage or palates to keep produce off the floor to

allow free air circulation, (ii) by ensuring that only one door is

open at a time and air locks are provided to reduce the heat load

in the cold store, (iii) by removing of produce in the store in the

same order that they were placed, (iv) by applying the principle

that fish should be frozen first in the deep freezer before stored

in the cold room, and (v) monitoring the samples in the store as

well as the cold store temperature at regular intervals.

21

3.5 Fish Marketing

In Nigeria there is the artisanal fish marketing and the

modern fish marketing of frozen fish.

3.5.1 Artisanal Fish Marketing

One typical fish marketing channel in the artisanal fishery

involves fishermen who sell fresh fish to fishmongers who may

process the fish in fishing villages before selling them to fish

traders who then will convey them to distant market places.

(Ladipo, Fabiyi and Fatunla, 1981). In some areas the wives of

fishermen purchase the fish from their husbands, process it and

sell it to fish traders.

Marketing channels for fresh and iced fish are not as clear

cut, but a significant channel identified in Kainji Lake area is

from the producer to wholesaler-retailers in urban centres such as

New Bussa, Yelwa, Kaduna, Enugu, Ibadan, Ilorin, and Lagos. These

wholesalers sell the frozen fish to itinerant wholesalers based in

the same market, or a commissioned agent. The last category of

middlemen then transport the frozen fish to the urban sedentary

wholesaler-retailer in the cities of Ibadan, Ilorin, Kaduna and

Lagos (Anthonio, 1995, see also for further information).

Only two registered co-operative societies are operating in

Kainji Lake basin. These are the Fresh Fish Co-operative Society

and Sarikawa Mabunta Co-operative Society both situated in Yauri.

The Fresh Fish Co-operative Society is actively involved in

the purchase, storage and sale of fresh fish to consumers.

21

3.5 Fish Marketing

In Nigeria there is the artisanal fish marketing and the

modern fish marketing of frozen fish.

3.5.1 Artisanal Fish Marketing

One typical fish marketing channel in the artisanal fishery

involves fishermen who sell fresh fish to fishmongers who may

process the fish in fishing villages before selling them to fish

traders who then will convey them to distant market places.

(Ladipo, Fabiyi and Fatunla, 1981). In some areas the wives of

fishermen purchase the fish from their husbands, process it and

sell it to fish traders.

Marketing channels for fresh and iced fish are not as clear

cut, but a significant channel identified in Kainji Lake area is

from the producer to wholesaler-retailers in urban centres such as

New Bussa, Yelwa, Kaduna, Enugu, Ibadan, Ilorin, and Lagos. These

wholesalers sell the frozen fish to itinerant wholesalers based in

the same market, or a commissioned agent. The last category of

middlemen then transport the frozen fish to the urban sedentary

wholesaler-retailer in the cities of Ibadan, Ilorin, Kaduna and

Lagos (Anthonio, 1995, see also for further information).

Only two registered co-operative societies are operating in

Kainji Lake basin. These are the Fresh Fish Co-operative Society

and Sarikawa Mabunta Co-operative Society both situated in Yauri.

The Fresh Fish Co-operative Society is actively involved in

the purchase, storage and sale of fresh fish to consumers.

22

The only storage facility available is a deep freezer owned by the

Kebbi State Government. The Society maintains the freezer and pays

for the electricity for the members to store their fresh fish in

the freezer. In case of electricity failure (in the absence of

generators) members have to hire deep freezers from private owners

in the town. Still, during prolonged power failure the society

experience losses due to spoilage. To prevent total loss previously

frozen fish are smoked and sold. Here again, the Society

experiences an economic loss since hiaher prices are paid for whole

frozen fish than smoked fish.

The second co-operative society has acquired a cold storaae

unit formerly owned by the Federal Government and located in the

vicinity of MANR Fisheries Division. This unit is made up of an ice

plant, a cold store, the Kainji Gas Smoking Kiln and a stand-by

generator. The society has also acquired two offices, one toilet

and one water tank. The society intends to buy a refrigerated van

to complete the cold chain. If all these facilities are put into

effective use, they will remarkably reduce post harvest losses in

the Yauri Area.

A similar cold store complex is available at Anfani consisting

of a cold room, an ice plant and a generator.

The office building attached is in need of refurbishing. The

complex has is owned by private entrepreneurs.

The equipment is functional but yet to be put into use.

22

The only storage facility available is a deep freezer owned by the

Kebbi State Government. The Society maintains the freezer and pays

for the electricity for the members to store their fresh fish in

the freezer. In case of electricity failure (in the absence of

generators) members have to hire deep freezers from private owners

in the town. Still, during prolonged power failure the society

experience losses due to spoilage. To prevent total loss previously

frozen fish are smoked and sold. Here again, the Society

experiences an economic loss since hiaher prices are paid for whole

frozen fish than smoked fish.

The second co-operative society has acquired a cold storaae

unit formerly owned by the Federal Government and located in the

vicinity of MANR Fisheries Division. This unit is made up of an ice

plant, a cold store, the Kainji Gas Smoking Kiln and a stand-by

generator. The society has aso acquired two offices, one toilet

and one water tank. The society intends to buy a refrigerated van

to complete the cold chain. If all these facilities are put into

effective use, they will remarkably reduce post harvest losses in

the Yauri Area.

A similar cold store complex is available at Anfani consisting

of a cold room, an ice plant and a generator.

The office building attached is in need of refurbishing. The

complex has is owned by private entrepreneurs.

The equipment is functional but yet to be put into use.

3.5.2 Marketing of Frozen Fish

Main actors (sellers) in frozen fish marketing are the fish

firms located in Lagos, Port Harcourt, Sapele and Warri. Their

customers are the agents, retailers or hawkers and institutional/

household consumers. There are more than 100 registered fishing

firms but only very few actually catch fish, the rest are only

involved in buying and selling.

The most dominant distributors of frozen fish are the dealers

who were essentially sales agents of the marketing firms such as

Ibru Ltd, Globe Ltd, Transcontinental Ltd etc. on a cash sales

basis with little or no attachment to the company. About 73% of the

dealer points were by 1981 independent dealers. Ibru and Globe

dealers control only 8% each of the dealer points. The other major

companies with national distribution network are Universal (6%),

Transcontinental Ltd (3%) and Sadia (0.4%) of the dealer point

across the nation (Iadipo et al, 1981). Fishing firms supply fish

to dealers in containers of 20 and 30kg. The retailers sell fish in

singles or cuts (Ladipo et al, 1981).

4. METHODOLOGY

4.1 Method of Data Collection

Information for the present study were collected through

literature review and a field survey. For the field work interviews

were carried out with standardised questionnaires.

2323

3.5.2 Marketing of Frozen Fish

Main actors (sellers) in frozen fish marketing are the fish

firms located in Lagos, Port Harcourt, Sapele and Warri. Their

customers are the agents, retailers or hawkers and institutional/

household consumers. There are more than 100 registered fishing

firms but only very few actually catch fish, the rest are only

involved in buying and selling.

The most dominant distributors of frozen fish are the dealers

whc were essentially sales agents of the marketing firms such as

Ibru Ltd, Globe Ltd, Transcontinental Ltd etc. on a cash sales

basis with little or no attachment to the company. About 73% of the

dealer points were by 1981 independent dealers. Ibru and Globe

dealers control only 8% each of the dealer points. The other malor

companies with national distribution network are Universal (6%),

Transcontinental Ltd (3%) and Sadia (0,4%) of the dealer point

across the nation (Ladipo et al, 1981). Fishing firms supply fish

to dealers in containers of 20 and 30kg. The retailers sell fish in

singles or cuts (Ladipo et al, 1981).

4. METHODOLOGY

4.1 Method of Data Collection

Information for the present study were collected through

literature review and a field survey. For the field work interviews

were carried out with standardised questionnaires.

24

4.2 Sample Population, Sample Size and Sampling Procedure

The sample population was chosen from the groups of

fishermen, fish processors, fish buyers and fish sellers.

For data collection purposes the Kainji Lake basin was divided

into 8 sub-strata. One base centre was chosen in each sub-stratum.

The data collectors spent 3 days in each centre. From the base

centre fishing villages within the neighbourhood were visited with

a motorised boat propelled with two 40 HP Engines. A total of 45

villages including the base centres were visited. The number of

people interviewed were 668 comprising 317 fisherfolk, 115 fish

processors, 125 fish buyers and 111 fish sellers (Annex 2). Since

the total population for each group of responde= was not known,

random sampling was not possible. Instead, respondents available at

point of the visit were interviewed within a given period of time.

The entire survey lasted for 24 days, starting on 22nd April 1986

and ending on 10th June 1996 (with three weeks break in between).

4.3 The Questionnaire

Four different questionnaires were designed targeting at the

different sample groups. Considering the scope of this study the

questionnaires did not include detailed demographic data but

reflected each of the various segments of post harvest technology:

fish handling losses, fish processing losses and fish marketing

losses for buyers and sellers respectively.

24

4.2 Sample Population, Sample Size and Sampling Procedure

The sample population was chosen from the groups of

fishermen, fish processors, fish buyers and fish sellers.

For data collection purposes the Kainji Lake basin was divided

into 8 sub-strata. One base centre was chosen in each sub-stratum.

The data collectors spent 3 days in each centre. From the base

centre fishing villages within the neighbourhood were visited with

a motorised boat propelled with two 40 HP Engines. A total of 45

villages including the base centres were visited. The number of

people interviewed were 668 comprising 317 fisherfolk, 115 fish

processors, 125 fish buyers and 111 fish sellers (Annex 2). Since

the total population for each group of responde=s was not known,

random sampling was not possible. Instead, respondents available at

point of the visit were interviewed within a given period of time.

The entire survey lasted for 24 days, starting on 22nd April 1986

and ending on 10th June 1996 (with three weeks break in between).

4.3 The Questionnaire

Four different questionnaires were designed targeting at the

different sample groups. Considering the scope of this study the

questionnaires did not include detailed demographic data but

reflected each of the various segments of post harvest technology:

fish handling losses, fish processing losses and fish marketing

losses for buyers and sellers respectively.

25

The questionnaire on fish handling losses was to obtain

information on the type of fishing gear used, the number and weight

of fish species caught and the proportion of spoilage after hauling

the net. The time of setting and checking the fishing nets and

landing the catch was also reflected.

The questionnaire on fish processing losses centred on the

types of fish processing methods employed by the fish processor for

the different fish species. Measurements of quantity and weight of

fish before and after processing were also included.

The focal point of the questionnaire on marketing losses for

fish buyers was to determine the quantity and weight of fish

purchased by the buyer and those discarded afterwards. Questions on

use of discarded fish were also included.

The questionnaire on marketing losses for fish sellers took

into consideration the quantity and weight of the catch spoilt or

discarded during marketing, the method of packaging the fish and

the causes of spoilage of the fish being marketed (Annex 3 and 4

for map of the study area and questionnaires).

The questionnaires were designed in English but translated

into Hausa and Pidgin English by the enumerators during the

interviews.

4.4 Training of Data Collectors

The interviews were carried out by twc male and two female

Hausa/English speaking data collectors under part-time supervis on

of a team leader.

25

The questionnaire on fish handling losses was to obtain

information on the type of fishing gear used, the number and weight

of fish species caught and the proportion of spoilage after hauling

the net. The time of setting and checking the fishing nets and

landing the catch was also reflected.

The questionnaire on fish processing losses centred on the

types of fish processing methods employed by the fish processor for

the different fish species. Measurements of quantity and weight of

fish before and after processing were also included.

The focal point of the questionnaire on marketing losses for

fish buyers was to determine the quantity and weight of fish

purchased by the buyer and those discarded afterwards. Questions on

use of discarded fish were also included.

The questionnaire on marketing losses for fish sellers took

into consideration the quantity and weight of the catch spoilt or

discarded during marketing, the method of packaging the fish and

the causes of spoilage of the fish being marketed (Annex 3 and 4

for map of the study area and questionnaires).

The questionnaires were designed in English but translated

into Hausa and Pidgin English by the enumerators during the

interviews.

4.4 Training of Data Collectors

The interviews were carried out by two male and two female

Hausa/English speaking data collectors under part-time supervis on

of a team leader.

26

During the initial training the data collectors were introduced to

the objective of the survey. Further, stepwise explanation of each

questionnaire/question was made. Using two publications ("An

illustrated key to fisheries of Lake Kainji" by D.S.C. Lewis and

"Fish and Fisheries of Northern Nigeria" by Reed et al (1965)) the

data collectors were taught how to identify the commercially

important fish species of Kainji lake. These books were also used

as reference documents on the field during the survey.

Two of the four data collectors were already knowledgeable in

the fisheries of Kainji Lake having worked there for more than

fifteen years as fisheries technical staff of NIFFR. They utilised

their vast experiences during the survey and assisted the other two

enumerators on species identification whenever they were in doubt.

The training of enumerators also included organoleptic

assessment of the quality of fresh and processed fish by observing

changes in the gills, eyes and the general appearance of the fish

using the sensory organs of touch, smell and sight.

Tables on quality changes in moonfish and trunk fish at ambient

temperature (Eyo, 1993b) were used for this purpose (Annex 5 & 6).

The three day training was followed by one day pre-test of

questionnaires at Anfani - a fishing village close to Kainji Dam.

26

During the initial training the data collectors were introduced to

the objective of the survey. Further, stepwise explanation of each

questionnaire/question was made. Using two publications ("An

illustrated key to fisheries of Lake Kainji" by D.S.C. Lewis and

"Fish and Fisheries of Northern Nigeria" by Reed et al (1965)) the

data collectors were taught how to identify the commercially

important fish species of Kainji lake. These books were also used

as reference documents on the field during the survey.

Two of the four data collectors were already knowledgeable in

the fisheries of Kainji Lake having worked there for more than

fifteen years as fisheries technical staff of NIFFR. They utilised

their vast experiences during the survey and assisted the other two

enumerators on species identification whenever they were in doubt.

The training of enumerators also included organoleptic

assessment of the quality of fresh and processed fish by observing

changes in the gills, eyes and the general appearance of the fish

using the sensory organs of touch, smell and sight.

Tables on quality changes in moonfish and trunk fish at ambient

temperature (Eyo, 1993b) were used for this purpose (Annex 5 & 6).

The three day training was followed by one day pre-test of

questionnaires at Anfani - a fishing village close to Kainji Dam.

27

4.5 Data Collection

To facilitate the data collection on arrival at the fishing

village or collection centre the enumerators paid a courtesy call

on the traditional leader to intimated him with the purpose of the

survey and to seek for permission to carry out data collection

among the fisherfolk within his jurisdiction.

Questionnaires on fish handling losses were administered to

fisherfolk during their active fishing time (7 am and 1 pm).

On-the-spot assessment of the fish quality was carried out

systematically in each boat at the landing site and sometimes on

the lake after the fishermen had hauled up their nets.

Questionnaires on fish processing_losses were administered to

migrant fish processors who hailed mainly from Edo, Delta and the

Eastern States and to sedentary fish processors who were mainly

fishermen's wives. This group could only be interviewed by the

female enumerators since most indigenous women around Kainji Lake

are not allowed to leave their compound and to talk to men other

than their husbands and close relatives. The interviews were

usually carried out between 2 pm and 6 pm.

Questionnaires on marketing losses were administered at the

market centres where fish sellers and buyers converge to transact

business. The data collectors visited all major markets in the lake

basin during the period of the survey.

27

4.5 Data Collection

To facilitate the data collection on arrival at the fishing

village or collection centre the enumerators paid a courtesy call

on the traditional leader to intimated him with the purpose of the

survey and to seek for permission to carry out data collection

among the fisherfolk within his jurisdiction.

Questionnaires on fish handling losses were administered to

fisherfolk during their active fishing time (7 am and 1 pm).

On-the-spot assessment of the fish quality was carried out

systematically in each boat at the landing site and sometimes on

the lake after the fishermen had hauled up their nets.

Questionnaires on fish processing losses were administered to

migrant fish processors who hailed mainly from Edo, Delta and the

Eastern States and to sedentary fish processors who were mainly

fishermen's wives. This group could only be interviewed by the

female enumerators since most indigenous women around Kainji Lake

are not allowed to leave their compound and to talk to men other

than their husbands and close relatives. The interviews were

usually carried out between 2 pm and 6 pm.

Questionnaires on marketing losses were administered at the

market centres where fish sellers and buyers converge to transact

business. The data collectors visited all major markets in the lake

basin during the period of the survey.

28

4.6 Equipment and Fish Weighing

Weighing balances of 50kg, 10kg and 5kg maximum capacity

respectively were used for weighing the fresh and processed fish.

In addition, two small and two medium size bowls were used for

storing the fish. In order to quantify the extent of fish losses

fish were sorted into the bowls by species. Spoiling fish were

separated from fish of desirable quality, and measurements of each

group were taken separately.

4.7 Assessment of Fish Quality

Raw fish samples were assessed by organoleptic evaluation of

the colour, odour, texture and appearance of the gills, flesh, skin

and the eyes using the guideline on quality scores and organoleptic

changes for Moonfish Citharinus citharus and Trunkfish Mormyrus

rume - raw samples.

For processed fish samples, changes in the odour from fresh

"smoky" to putrescent and texture were used to either accept the

fish or reject it as spoiled.

5. RESULT AND DISCUSSION

5.1 Fish Catch

During sampling, the total number of fish caught was 24,839

(2389.3kg) from 43 fish species (Annex 7). Oreochromis niloticus

was the dominant species by weight (357.27kg), followed by Lates

niloticus (210.31kg), Citharinus citharus (193.7kg)1 Synodontis

membranaceous (164.12kg) and Labe° senegalensis (159.63kg).

28

4.6 Equipment and Fish Weighing

Weighing balances of 50kg, 10kg and 5kg maximum capacity

respectively were used for weighing the fresh and processed fish.

In addition, two small and two medium size bowls were used for

storing the fish. In order to quantify the extent of fish losses

fish were sorted into the bowls by species. Spoiling fish were

separated from fish of desirable quality, and measurements of each

group were taken separately.

4.7 Assessment of Fish Quality

Raw fish samples were assessed by organoleptic evaluation of

the colour, odour, texture and appearance of the gills, flesh, skin

and the eyes using the guideline on quality scores and organoleptic

changes for Moonfish Citharinus citharus and Trunkfish Mormvrus

rume - raw samples.

For processed fish samples, changes in the odour from fresh

"smoky" to putrescent and texture were used to either accept the

fish or reject it as spoiled.

5. RESULT AND DISCUSSION

5.1 Fish Catch

During sampling, the total number of fish caught was 24,839

(2389.3kg) from 43 fish species (Annex 7). Oreochromis niloticus

was the dominant species by weight (357.27kg), followed by Lates

niloticus (210.31kg), Citharinus citharus (193.7kg)1 Synodontis

membranaceous (164.12kg) and Labeo senegalensis (159.63kg).

29

5.2 Fish Spoilage at Checking and Landing

At checking, Clarias anquillaris 3 had the highest spoilage

rate with 23% by wt closely followed by Alestes macrolepidotus

(22%), Distichodus brevipinnus (22%) and Hydrocynus forskalii

(18%). The least percentage loss at checking was 0.33% from

Auchonoglanis biscullatus (Annex 9).

At landing labeo senegalensis recorded the highest level of

spoilage by wt (17.36%) followed by Chrysichthys auratus (8.49%),

Labeo coubie (5.67%) and Hvdrocvnus forskalii (5%). The least

spoilage was observed in Chrysichthys nigrodigitatus with less than

1%. Oreochromis niloticus that was highest in catch had 10%

spoilage at checking and 4% at landing.

No spoilage was recorded either at checking or landing for the

following species: Sierrathrissa leonensis, Alestes baremose,

Hydrocvnus brevis, Labeo loseudocoubie, Synodontis batensoda,

Synodontis qambiensis, Sarotherodon qalilaeus, Tilapia

Heterobranchus bidorsalis and Gvmnarchus niloticus for the

following reasons:

they were either caught with active gears and therefore did not

spend long time in the water before checking and landing

(Sierrathrissa leonensis and seine net by-catches),

3For common names of fish species see Annex 8

29

5.2 Fish Spoilage at Checking and Landing

At checking, Clarias anguillaris 3 had the highest spoilage

rate with 23% by wt closely followed by Alestes macrolepidotus

(22%), Distichodus brevipinnus (22%) and Hydrocynus forskalii

(18%). The least percentage loss at checking was 0.33% from

Auchonoglanis biscullatus (Annex 9).

At landing labeo senegalensis recorded the highest level of

spoilage by wt (17.36%) followed by Chrysichthys auratus (8.49%),

Labeo coubie (5.67%) and Hydrocynus forskalii (5%). The least

spoilage was observed in Chrysichthys nigrodigitatus with less than

1%. Oreochromis niloticus that was highest in catch had 10%

spoilage at checking and 4% at landing.

No spoilage was recorded either at checking or landing for the

following species: Sierrathrissa leonensis, Alestes baremose,

Hydrocvnus brevis, Labeo loseudocoubie, Synodontis batensoda,

Synodontis gambiensis, Sarotherodon galilaeus, Tilapia

Heterobranchus bidorsalis and Gymnarchus niloticus for the

following reasons:

they were either caught with active gears and therefore did not

spend long time in the water before checking and landing

(Sierrathrissa leonensis and seine net by-catches),

3For common names of fish species see Annex 8

30

they were too few in the catch samples measured to make any

meaningful impact.

they have ancillary breathing organs which enable them to stay

alive for many hours in the net until the fish is landed (e.g.

Synodontis sp.).

In general spoilage at checking and landing were higher in the

fatty species than the lean fish. This shows that the oxidation of

fat in the pelagic species was more significant in causing off

flavour than bacteria action on the fish.

5.3 Fish Spoilage according to Gear

Fish that deteriorate in the nets are bleached and dull having

been water-logged in the lake. They can easily be distinguished

from those that deteriorate after hauling since they seldom lose

the distinct natural skin coloration.

In the sample gillnets accounted for 79% of the fishing gears

used by the artisanal fishermen followed by cast nets (9%), hooks

(7%), traps (4%) and beach seines (1.4%).

Catches from gillnets were the highest accounting for 78%

by wt of the total fish caught. This was followed by cast nets

(10%) and hooks/longlines (7%). Traps and beach seine catches were

3% and 1.5% respectively (Table 5.1).

As indicated above the likelihood of fish spoilage in passive

fishing gear (e.g. gillnet) is higher than in active gears (e.g.

seine nets).

30

they were too few in the catch samples measured to make any

meaningful impact.

they have ancillary breathing organs which enable them to stay

alive for many hours in the net until the fish is landed (e.g.

Synodontis sp.).

In general spoilage at checking and landing were higher in the

fatty species than the lean fish. This shows that the oxidation of

fat in the pelagic species was more significant in causing off

flavour than bacteria action on the fish.

5.3 Fish Spoilage according to Gear

Fish that deteriorate in the nets are bleached and dull having

been water-logged in the lake. They can easily be distinguished

from those that deteriorate after hauling since they seldom lose

the distinct natural skin coloration.

In the sample gillnets accounted for 79% of the fishing gears

used by the artisanal fishermen followed by cast nets (9%), hooks

(7%), traps (4%) and beach seines (1.4%).

Catches from gillnets were the highest accounting for 78%

by wt of the total fish caught. This was followed by cast nets

(10%) and hooks/longlines (7%). Traps and beach seine catches were

3% and 1.5% respectively (Table 5.1).

As indicated above the likelihood of fish spoilage in passive

fishing gear (e.g. gillnet) is higher than in active gears (e.g.

seine nets).

31

Beach seine catches:

Beach seine catches did not show any deterioration at checking

and landing. This was expected since setting and landing are

completed in less than an hour and most fish are actually brought

alive to the shore.

Gillnet catches:

Caught in gillnets the fish begin to struggle and may die of

exhaustion. Fish caught early may begin to spoil long before the

nets are hauled up.4

Gillnet catches accounted for 96% of the total fish spoilt at

checking and landing.

Of the total sample catch assessed 10.5% was spoiled at

checking and additional 3% got spoilt until the catch was finally

landed (Table 5.1). Extrapolated using the 1995 catch figures for

Kainji Lake (Catch Assessment Survey of KLFPP) out of the total

gillnet landings of 5,778t about 606t were spoilt at checking and

173t were spoilt at landing, accumulating to 779t of loss of fish

per year (Table 5.2).

Hooks/Longlines catches:

Longlines accounted for 7% by wt of the total amount of spoilt

fish recorded. No additional spoilage was noticed until the fish

was finally landed.

4 Fish are usually caught in gillnets in one of threeways: Fish may be caught at the larger middle partof the body as they attempt to swim through the netor the net may enter behind the gill covers or thewhole fish may get entangled in the net while tryingto pass through.

31

Beach seine catches:

Beach seine catches did not show any deterioration at checking

and landing. This was expected since setting and landing are

completed in less than an hour and most fish are actually brought

alive to the shore.

Gillnet catches:

Caught in gillnets the fish begin to struggle and may die of

exhaustion. Fish caught early may begin to spoil long before the

nets are hauled up.4

Gillnet catches accounted for 96% of the total fish spoilt at

checking and landing.

Of the total sample catch assessed 10.5% was spoiled at

checking and additional 3% got spoilt until the catch was finally

landed (Table 5.1). Extrapolated using the 1995 catch figures for

Kainji Lake (Catch Assessment Survey of KLFPP) out of the total

gillnet landings of 5,778t about 606t were spoilt at checking and

173t were spoilt at landing, accumulating to 779t of loss of fish

per year (Table 5.2).

Hooks/Longlines catches:

Longlines accounted for 7% by wt of the total amount of spoilt

fish recorded. No additional spoilage was noticed until the fish

was finally landed.

4 .Fish are usually caught in gillnets in one of threeways: Fish may be caught at the larger middle partof the body as they attempt to swim through the netor the net may enter behind the gill covers or thewhole fish may get entangled in the net while tryingto pass through.

32

Extrapolated to the total of 1995 fish catches about 28.6t of

fish caught in longlines were spoilt (Table 5.2).

Fish trap catches:

About 3% of the fish that was spoilt at checking was caught in

traps. No additional fish spoilage was recorded between checking

and landing (Table 5.1).

The total estimates of fish spoilage of trap catches amounted

to 117.8t in 1995 (Table 5.2).

Cast net catches:

Cast nets are active fishing gears. The spoilage noticed was

associated with the delay in conveying fish caught early to the

shore since fishermen cast their nets many times over several hours

to catch enough fish before they are landed.

From the total amount of fish spoilt during sampling 10% by wt

at checking and 11% at landing were caught in castnets.

From a total cast net catch of 4,139t in 1995 about 136.6t got

spoiled either at checking or at landing (Table 5.2).

Considering the total catch from gillnets, longlines, traps

and castnets of about estimated 14,000t in 1995 about 1,000t of

fish lost value or had to be discarded due to spoilage. Assuming an

average price of 80 Naira per kg of fish the loss to the economy

amounts to 80 million Naira per year (on the basis of 1995 figures)

32

Extrapolated to the total of 1995 fish catches about 28.6t of

fish caught in longlines were spoilt (Table 5.2).

Fish trap catches:

About 3% of the fish that was spoilt at checking was caught in

traps. No additional fish spoilage was recorded between checking

and landing (Table 5.1).

The total estimates of fish spoilage of trap catches amounted

to 117.8t in 1995 (Table 5.2).

Cast net catches:

Cast nets are active fishing gears. The spoilage noticed was

associated with the delay in conveying fish caught early to the

shore since fishermen cast their nets many times over several hours

to catch enough fish before they are landed.

From the total amount of fish spoilt during sampling 10% by wt

at checking and 11% at landing were caught in castnets.

From a total cast net catch of 4,139t in 1995 about 136.6t got

spoiled either at checking or at landing (Table 5.2).

Considering the total catch from gillnets, longlines, traps

and castnets of about estimated 14,000t in 1995 about 1,000t of

fish lost value or had to be discarded due to spoilage. Assuming an

average price of 80 Naira per kg of fish the loss to the economy

amounts to 80 million Naira per year (on the basis of 1995 figures)

33

Table 5.1: Fish Spoilage (sample) according to Fishing Gear

GN = Gillnet, LL = Longline, TR = Fishing Trap, BS - Beach Seine

CN = Cast Net

Gear

No

Catch

(kg)

% tot

Wt

% tot

Spoilage at Checking

No

% tot

Wt

% tot

Spoilage at Landing

No

% tot

Wt

% tot

GN

19738 79.5

1869.0 78.2

2517 97.4

196.2

96

898

93.7

63.3

89.3

LL

1279

5.2

173.7

7.3

20

0.8

21.0

TR

1609

6.5

82.1

3.4

44

1.7

5.7

2.8

BS

18

0.1

36.7

1.5

CN

2195

8.9

227.8

9.5

40.2

0.6

0.3

60

6.3

7.6

10.7

Tot. 24839

238.9

2585 10.4

204.5

8.6

958

3.9

70.9

3.0

33

Table 5.1: Fish Spoilage (sample) according to Fishing Gear

GN = Gillnet, LL = Longline, TR = Fishing Trap, BS - Beach Seine

CN = Cast Net

Gear

No

Catch

(kg)

96 tot

Wt

96 tot

Spoilage at Checking

No

% tot

Wt

96tot

Spoilage at Landing

No

96tot

Wt

% tot

GN

19738 79.5

1869.0 78.2

2517 97.4

196.2

96

898

93.7

63.3

89.3

LL

1279

5.2

173.7

7.3

20

0.8

21.0

TR

1609

6.5

82.1

3.4

44

1.7

5.7

2.8

BS

18

0.1

36.7

1.5

CN

2195

8.9

227.8

9.5

40.2

0.6

0.3

60

6.3

7.6

10.7

Tot. 24839

238.9

2585 10.4

204.5

8.6

958

3.9

70.9

3.0

34

Table 5.2: Fish Spoilage (total) according to Fishing Gear

GN = Gillnet, LL = Longline, TR = Fishing Trap, BS = Beach Seine

CN = Castnet

Gear Catch (total)

(t)

Spoilage at Checking

(t)

(9,5)

Spoilage at Landing

(t)

(9,5)

Total

(t)

(9,5)

GN

5778

606

10.5

173

3779

13.5

LL

2383

28.6

1.2

28.6 1.2

TR

1707

117.8

6.9

117.8 6.9

CN

4139

12.4

0.3

136.6

3.3

149

3.3

Tot.

14007

1074.4 7.6

34

Table 5.2: Fish Spoilage (total) according to Fishing Gear

GN = Gillnet, LL = Longline, TR = Fishing Trap, BS = Beach Seine

CN = Castnet

Gear Catch (total)

(t)

Spoilage at Checking

(t)

(%)

Spoilage at Landing

(t)

(96-)

Total

(t)

(9,5)

GN

5778

606

10.5

173

3779

13.5

LL

2383

28.6

1.2

28.6 1.2

TR

1707

117.8

6.9

117.8 6.9

CN

4139

12.4

0.3

136.6

3.3

149

3.3

Tot.

14007

1074.4 7.6

35

5.4 Fish Spoilage in Relation to Fishing Time by Gear

Passive gears such as gillnets and fishing traps were mainly

set in the evening and checked before noon. Active gears e.g. cast-

nets and beach seine were operated at any time of the day. In

addition beach seines for clupeids were operated almost hourly

throughout the day/night.

Gillnets:

The relationship between setting time and spoilage of gillnet

catches at checking and landing is set out in Table 5.3.

The majority of gillnets (8426) were set between 1 pm - 7 pm, 8%

between 6 am - 1 pm, 6% between 12 midnight - 6 am and 2% between

7 pm - 12 midnight.

Nets set in the afternoon recorded the highest catches of 83%

by weight. They also recorded the highest spoilage rate amounting

to 85% by wt at checking and 77% by wt at landing because they were

left a long time in the lake before checking (min. 10 hrs, max. 27

hrs, avg. 14.5 hrs, Table 5.4).

Gillnets set between 6 am and 1 pm were left without checking

for 19 to 34 hours with an average of 24.45 hours.

The long hours of fishing significantly influence the rate of

spoilage since fish caught early in net may struggle and die of

asphyxia long before the nets are hauled up.

35

5.4 Fish Spoilage in Relation to Fishing Time by Gear

Passive gears such as gillnets and fishing traps were mainly

set in the evening and checked before noon. Active gears e.g. cast-

nets and beach seine were operated at any time of the day. In

addition beach seines for clupeids were operated almost hourly

throughout the day/night.

Gillnets:

The relationship between setting time and spoilage of gillnet

catches at checking and landing is set out in Table 5.3.

The majority of gillnets (84%) were set between 1 pm - 7 pm, 8%

between 6 am - 1 pm, 6% between 12 midnight - 6 am and 2% between

7 pm - 12 midnight.

Nets set in the afternoon recorded the highest catches of 83%

by weight. They also recorded the highest spoilage rate amounting

to 85% by wt at checking and 77% by wt at landing because they were

left a long time in the lake before checking (min. 10 hrs, max. 27

hrs, avg. 14.5 hrs, Table 5.4).

Gillnets set between 6 am and 1 pm were left without checking

for 19 to 34 hours with an average of 24.45 hours.

The long hours of fishing significantly influence the rate of

spoilage since fish caught early in net may struggle and die of

asphyxia long before the nets are hauled up.

Table 5.4 Duration of Fishing with Gillnets

36

Table 5.3 Spoilage of Gillnet Catches according to Fishing Time

% Fish

caught

in no

% Fish

caught

in wt

% Spoilt

at checkg.

in no

% Spoilt

at checkg.

in wt

% Spoilt

at landg.

in no

% Spoilt

at landg.

in wt

12

- 6am

3.3

4.1

2.2

4.1

1.5

2.8

6am - lpm

15.3

9.6

12.2

8.8

9.1

14.9

lpm - 7pm

72.9

83.0

83.3

85.4

87.7

77.2

7pm -

12

8.5

3.3

2.3

1.7

1.7

5.1

12

34

56

12

-6am

12.2

34

16.3

0.3

10

3.3

6am - lpm

19

34

24.5

0.2

9.3

3.2

lpm - 7pm

10

27

14.5

0.1

9.2

3

7pm - 12

514

9.2

0.3

9.3

5

1Mimimum time between setting and checking of gillnet (hrs.)

2Maximum time between setting and checking of gillnet (hrs.)

3Average time between setting and checking of gillnet

(hrs.)

4Mimimum time between checking and landing of gillnet (hrs.)

5Maximum time between checking and landing of gillnet (hrs.)

6Average time between checking and landing of

gillnet (hrs.)

Table 5.4 Duration of Fishing with Gillnets

36

Table 5.3 Spoilage of Gillnet Catches according to Fishing Time

% Fish

caught

in no

% Fish

caught

in wt

95 Spoilt

at checkg.

in no

% Spoilt

at checkg.

in wt

96'Spoilt

at landg.

in no

96 Spoilt

at landg.

in wt

12

- 6am

3.3

4.1

2.2

4.1

1.5

2.8

6am - 1pm

15.3

9.6

12.2

8.8

9.1

14.9

lpm - 7pm

72.9

83.0

83.3

85.4

87.7

77.2

7pm - 12

8.5

3.3

2.3

1.7

1.7

5.1

12

34

56

12

- 6am

12.2

34

16.3

0.3

10

3.3

6am - lpm

19

34

24.5

0.2

9.3

3.2

lpm - 7pm

10

27

14.5

0.1

9.2

3

7pm - 12

514

9.2

0.3

9.3

5

1Mimimum time between setting and checking of gillnet (hrs.)

2Maximum time between setting and checking of gillnet (hrs.)

3Average time between setting and checking of gillnet

(hrs.)

4Mimimum time between checking and landing of gillnet (hrs.)

5Maximum time between checking and landing of gillnet (hrs.)

6Average time between checking and landing of gillnet

(hrs.)

37

Longlines:

The setting time and duration of fishing with longlines/hooks

is shown in Table 5.5. Most of the hooks (73%) were set between

1 pm - 7 pm, about 23% between 6 am - 1 pm and only one hook (4%)

was set between 7 pm - 12 midnight.

Like for gillnets most spoilage was noticed at checking hooks

that were set in the late afternoon and evening hours (Table 5.5).

Table 5.6 shows that fish on the hooks remained for 6 - 21 hours in

the water before checking. This was enough time for dead fish to

pass through rigor mortis and begin to deteriorate.

37

Longlines:

The setting time and duration of fishing with longlines/hooks

is shown in Table 5.5. Most of the hooks (73%) were set between

1 pm - 7 pm, about 23% between 6 am - 1 pm and only one hook (4%)

was set between 7 pm - 12 midnight.

Like for gillnets most spoilage was noticed at checking hooks

that were set in the late afternoon and evening hours (Table 5.5).

Table 5.6 shows that fish on the hooks remained for 6 - 21 hours in

the water before checking. This was enough time for dead fish to

pass through rigor mortis and begin to deteriorate.

38

Table 5.5 Spoilage of Longline Catches according to

Fishing Time

12

- 6am

6am - lpm

lpm - 7pm

7pm - 12

% Fish

caught

in no

86

13.5

0.5

% Fish

caught

in wt

24.7

73.3

2

Table 5.6 Duration of Fishing with Longlines

96Spoilt

at landg.

in wt

96Spoilt

at checkg.

in no

.-

-,Spoilt

at checkg.

in wt

% Spoilt

at landg.

in no

100

100

23

45

6

12

- 6am

Gam - 1pm

12

21.3

15.3

18.2

3.2

1pm - 7pm

621

14.5

14

3.2

7pm - 12

1Mimimum time between setting and checking of longlines

(hrs.)

2Maximum time between setting and checking of

longlines (hrs.)

3Average time between setting and checking

of longlines (hrs.)

4Mimimum time between checking and landing of

longlines (hrs.)

5Maximum time between checking and landing of

longlines (hrs.)

6Average time between checking and landing

of longlines (hrs.)

Table 5.5 Spoilage of Longline Catches according to

Fishing Time

12

- 6am

6am - lpm

lpm - 7pm

7pm -

12

% Fish

caught

in no

86

13.5

0.5

% Fish

caught

in wt

24.7

73.3

2

Table 5.6 Duration of Fishing with Longlines

38

% Spoilt

at landg.

in wt

í

% atin

Spoilt

checkg.

no

% at in

Spoilt

checkg.

wt

% atin

Spoilt

landg.

no

100

100

23

45

6

12

- 6am

Gam - 1pm

12

21.3

15.3

18.2

3.2

1pm - 7pm

621

14.5

14

3.2

7pm - 12

1Mimimum time between setting and checking of

longlines (hrs.)

2Maximum time between setting and checking of

longlines (hrs.)

3Average time between setting and checking

of longlines (hrs.)

4Mimimum time between checking and landing of

longlines (hrs.)

5Maximum time between checking and landing of

longlines (hrs.)

6Average time between checking and landing

of longlines (hrs.)

3 9

Fishing traps:

About 69% of the fish traps set between 1 pm - 7 pm while 23%

was set between 6 am -1 pm and 8% was set between 7 - 12 midnight.

Most of the fish were caught in traps set between 1pm and 7pm

(Table 5.7). Again the duration of fishing influences significantly

the rate of spoilage at checking of fish caught in the trap. Fish

in traps spent between 13 and 30 hrs before being removed (Table

5.8). Although fish are often caught alive many die of exhaustion

while struggling in the limited space and hence show signs of

incipient spoilage.

3 9

Fishing traps:

About 699r, of the fish traps set between 1 pm - 7 pm while 2396-

was set between 6 am -1 pm and 896- was set between 7 - 12 midnight.

Most of the fish were caught in traps set between lpm and 7pm

(Table 5.7). Again the duration of fishing influences significantly

the rate of spoilage at checking of fish caught in the trap. Fish

in traps spent between 13 and 30 hrs before being removed (Table

5.8). Although fish are often caught alive many die of exhaustion

while struggling in the limited space and hence show signs of

incipient spoilage.

40

Table 5.7 Spoilage of Trap Catches according to Fishing Time

Table 5.8 Duration of Fishing with Fishing Traps

96 Fish

caught

in no

96 Fish

caught

in wt

% Spoilt

at checkg.

in no

% Spoilt

at checkg.

in wt 96

96Spoilt

at landg.

in no

96 Spoilt

at landg.

in wt

12

- 6am

6am -

lpm

32.1

26

100

100

lpm - 7pm

66.7

71.8

7pm -

12

1.2

2.2

12

34

56

12

- 6am

6am - lpm

22

24

23

0.5

1.3

1.3

lpm - 7pm

13

30

16.3

0.3

42.2

7pm -

12

1Mimimum time between setting and checking of fishing traps

2Maximum time between setting and checking of fishing traps

3Average time between setting and checking of fishing traps

4Mimimum time between checking and landing of fishing traps

5Maximum time between checking and landing of fishing traps

6Average time between checking and landing of fishing traps

40

Table 5.7 Spoilage of Trap Catches according to Fishing Time

Table 5.8 Duration of Fishing with Fishing Traps

and

and

and and

and

and

96 Fish

caught

in no

% Fish

caught

in wt

% Spoilt

at checkg.

in no

96Spoilt

at checkg.

in wt

96-

96'Spoilt

at landg.

in no

96 Spoilt

at landg.

in wt

12

- 6am

6am -

1pm

32.1

26

100

100

lpm - 7pm

66.7

71.8

7pm -

12

1.2

2.2

12

34

56

12

- 6am

6am - 1pm

22

24

23

0.5

1.3

1.3

lpm -

7pm

13

30

16.3

0.3

42.2

7pm -

12

1Mimimum time between setting

2Maximum time between setting

3Average time between setting

4Mimimum time between checking

5Maximum time between checking

6Average time between checking

checking of fishing traps

checking of fishing traps

checking of fishing traps

landing of fishing traps

landing of fishing traps

landing of fishing traps

41

5.5 Losses due to Bad Handling

The total fish spoilage was about 10% by number and 9% by

weight. Spoilage was higher at checking than at landing (4% by

number and 3% by weight) amounting to a total of 14% by number and

12% by weight.

Fish being removed from fishing gears are sometimes roughly

handled and most of the times dropped in the open at the canoe

bottoms under the prevailing high temperatures. Rapid deterioration

particularly through bacterial decomposition under the warm

conditions sets on. Fish that suffers bacterial putrefaction

whether they are later smoked or sun dried are generally unsuitable

for long distant transportation because of rapid deterioration in

storage. Such infested fish are usually rejected by consumers due

to their soft texture. This constitutes an additional loss to the

fish processor. Another source of loss is unsanitary way of gutting

fresh fish and throwing of wastes all around the processing sites.

These practices contribute to the rapid infestation of fish by

blowflies particularly Chrysomya sp. and the common housefly, Musca

domestica.

The blowflies oviposit on fish being prepared for smoking and

inadequate smoking does not kill the eggs. The ravaging effect of

the emerging larvae on partly dried fish reduces the quality of the

fishing product and the income accruing to the fish monger.

41

5.5 Losses due to Bad Handling

The total fish spoilage was about 10% by number and 9% by

weight. Spoilage was higher at checking than at landing (4% by

number and 3% by weight) amounting to a total of 14% by number and

12% by weight.

Fish being removed from fishing gears are sometimes roughly

handled and most of the times dropped in the open at the canoe

bottoms under the prevailing high temperatures. Rapid deterioration

particularly through bacterial decomposition under the warm

conditions sets on. Fish that suffers bacterial putrefaction

whether they are later smoked or sun dried are generally unsuitable

for long distant transportation because of rapid deterioration in

storage. Such infested fish are usually rejected by consumers due

to their soft texture. This constitutes an additional loss to the

fish processor. Another source of loss is unsanitary way of gutting

fresh fish and throwing of wastes all around the processing sites.

These practices contribute to the rapid infestation of fish by

blowflies particularly Chrysomya sp. and the common housefly, Musca

domestica.

The blowflies oviposit on fish being prepared for smoking and

inadequate smoking does not kill the eggs. The ravaging effect of

the emerging larvae on partly dried fish reduces the quality of the

fishing product and the income accruing to the fish monger.

42

5.6 Fish Processing - and Processing Losses

In the survey the major fish processing method was fish smoking

(and burning) accounting for 89% of the sample.

Smoking was mainly done by female fish processors (57%), who

are mostly fishermen's wives, or by migrant fish traders. Sun drying

which was conducted only by fishermen accounted for 10% of the

sample while frying accounted for less than 1%.

5.6.1 Fish Smoking

In the sample a total of 9,495 fishes weighing 987.18kg was

purchased by fish processors out of which 21% by number and 15% by

weight was spoilt before smoking. This suggests tha t fish processors

purchased spoiling fish from fishermen or left some of the good

quality fish to deteriorate believing tha t smoking would mask the

spoilage. Bu t since smoking does no t improve the quality of spoilt

fish such smoked product have off odour and break easily. Only 1% of

fish by number and less than 1% by weight deteriorated after smoking

which shows tha t the fish processors were in full control of the

smoking process. Fish were seldom gutted before smoking resulting in

enhanced bacterial spoilage and bitter tase due to bile.

Fish tha t are insufficiently dried-smoked having moisture

content of 40% or more are prone to attack by Rhizoctonia sp.,

Penicillin sp. and Aspergillus sp.

42

5.6 Fish Processing - and Processing Losses

In the survey the major fish processing method was fish smoking

(and burning) accounting for 89% of the sample.

Smoking was mainly done by female fish processors (57%), who

are mostly fishermen's wives, or by migrant fish traders. Sun drying

which was conducted only by fishermen accounted for 10% of the

sample while frying accounted for less than 1%.

5.6.1 Fish Smoking

In the sample a total of 9,495 fishes weighing 987.18kg was

purchased by fish processors out of which 21% by number and 15% by

weight was spoilt before smoking. This suggests that fish processors

purchased spoiling fish from fishermen or left some of the good

quality fish to deteriorate believing that smoking would mask the

spoilage. But since smoking does not improve the quality of spoilt

fish such smoked product have off odour and break easily. Only 1% of

fish by number and less than 1% by weight deteriorated after smoking

which shows that the fish processors were in full control of the

smoking process. Fish were seldom gutted before smoking resulting in

enhanced bacterial spoilage and bitter taste due to bile.

Fish that are insufficiently dried-smoked having moisture

content of 40% or more are prone to attack by Rhizoctonia sp.,

Penicillin sp. and Aspergillus sp.

43

In a survey of Ilorin fish markets and Faku (Kainji Lake District)

samples of smoked fish brought into the laboratory started becoming

mouldy about the third day of storage (Eyo and Awoyemi, 1990).

To check these types of infestation re-drying or re-smoking

before sale is often necessary, resulting in an increase of

processing costs. These costs are passed then to the consumers.

Data on the actual losses of dried/smoked fish due to fungi

infestation are rare in literature. However, personal observation

at the major fishing villages and markets in the Kainji Lake basin

revealed that substantial quantities of fish are usually infested

by fungal growth.

Before smoking the fish were usually not brined or salted.

They were loaded directly into the traditional "Banda" (73%) or a

variation of other types of smoking kilns (Annex 10). Pit smokers

are very common on Foge Island were fishermen are highly migratory

due to the changing water level.

Smoke was produced in all the smoking ovens by burning wood.

In a few cases dried cow dung was added to the fire at intervals

because it imparts a golden brown coloration to the smoked fish.

Dried cow dung reduces wood consumption and therefore costs since

t is available free of charge.

The duration of smoking is about a day or two depending on the

availability of fuel wood. During smoking in "banda" ovens the fish

loses over 50% of its weight (Table 5.9).

43

In a survey of Ilorin fish markets and Faku (Kainji Lake District)

samples of smoked fish brought into the laboratory started becoming

mouldy about the third day of storage (Eyo and Awoyemi, 1990).

To check these types of infestation re-drying or re-smoking

before sale is often necessary, resulting in an increase of

processing costs. These costs are passed then to the consumers.

Data on the actual losses of dried/smoked fish due to fungi

infestation are rare in literature. However, personal observation

at the major fishing villages and markets in the Kainji Lake basin

revealed that substantial quantities of fish are usually infested

by fungal growth.

Before smoking the fish were usually not brined or salted.

They were loaded directly into the traditional "Banda" (73%) or a

variation of other types of smoking kilns (Annex 10). Pit smokers

are very common on Foge Island were fishermen are highly migratory

due to the changing water level.

Smoke was produced in all the smoking ovens by burning wood.

In a few cases dried cow dung was added to the fire at intervals

because it imparts a golden brown coloration to the smoked fish.

Dried cow dung reduces wood consumption and therefore costs since

it is available free of charge.

The duration of smoking is about a day or two depending on the

availability of fuel wood. During smoking in "banda" ovens the fish

loses over 50% of its weight (Table 5.9).

44

Table 5.9: Losses in Weight of Fish during Fish Smoking with"Banda" Ovens.

5.6.2 Sun Drying

During the survey clupeids was the only fish that was sun

dried around Kainji Lake. The most popular clupeid catching area

was Foge Island. Clupeid fishery was carried out on Foge any time

of day or night.

When caught in the day, clupeids were immediately spread out

either on cemented floor or polythene sheets with little or no

spoilage since they dry within twelve hours.

Spoilage of clupeids can occurs when the night catch are

stored in a pouch net inside the canoe or left exposed for drying

the following morning.

Spoilt dried clupeids can be distinguished from the good

quality ones by the colour. Clupeids that are immediately dried

after landing are light brown with some sheen. Dried clupeids that

were spoilt before processing are greyish and dull.

Species No offish

Freshweight/kg

Driedweight/kg

96. Lossinwt

Alestes nurse 8 0.2 0.1 50BacTrus bavad 11 11.54 4.95 57Chrysitchys auratus 50 1 0.6 40Chrysitchys nigrodigitatus 1 0.4 0.1 75Citharinus citharus 1 0.38 0.1 74Clarotis laticeps 9 1.7 0.5 71Hyperopesius bebeoccidentalis 3 1.95 1.0 49Lates niloticus 7 13.6 5.92 56Mormyrus rume 1 1.6 0.85 47Oreochromis niloticus 10 0.7 0.4 43Svnodontis membranaceous 10 2.25 1.1 51

Total 35.32 15.62 56

44

Table 5.9: Losses in Weight of Fish during Fish Smoking with"Banda" Ovens.

5.6.2 Sun Drying

During the survey clupeids was the only fish that was sun

dried around Kainji Lake. The most popular clupeid catching area

was Foge Island. Clupeid fishery was carried out on Foge any time

of day or night.

When caught in the day, clupeids were immediately spread out

either on cemented floor or polythene sheets with little or no

spoilage since they dry within twelve hours.

Spoilage of clupeids can occurs when the night catch are

stored in a pouch net inside the canoe or left exposed for drying

the following morning.

Spoilt dried clupeids can be distinguished from the good

quality ones by the colour. Clupeids that are immediately dried

after landing are light brown with some sheen. Dried clupeids that

were spoilt before processing are greyish and dull.

Species No offish

Freshweight/kg

Driedweight/kg

% Lossinwt

Alestes nurse 8 0.2 0.1 50Bacfrus bayad 11 11.54 4.95 57Chrysitchys auratus 50 1 0.6 40Chrysitchys nigrodicritatus 1 0.4 0.1 75Citharinus citharus 1 0.38 0.1 74Clarotis laticeps 9 1.7 0.5 71Hyperopesius bebeoccidentalis 3 1.95 1.0 49Lates niloticus 7 13.6 5.92 56Mormyrus rume 1 1.6 0.85 47Oreochromis niloticus 10 0.7 0.4 43Synodontis membranaceous 10 2.25 1.1 51

Total 35.32 15.62 56

45

Clupeids with signs of spoilage lose market value by 30%. (e.g.

Naira 1,200 is paid per 50kg bag of freshly dried clupeids whereas

the dull product are sold for Naira 700-800). In the drying process

clupeids may lose up to 799,1 of its fresh weight with an average of

519s loss in weight (Table 5.10) due to moisture loss and/or attack

by vermin such as ducks.

Table 5.10 Loss in Weight during Sun Drying of Clupeids

5.6.3 Fish Burning

During the survey, fish burning was observed in Tada Monai. In

the process small fish (50-150g) are packed into dry grass that is

ignited with a smouldering wood. The fish is then burnt for about

15 minutes. After burning they cool in the ash for one hour. The

burnt fish are then transferred to the "Banda" and smoked

overnight.

Tab e 5.11 shows changes in fish weight during the

burning/smoking process. The low weight loss due to burning shows

that burning is not conducted to eliminate moisture per se but to

impart the dark appearance prior to smoking.

Batch No. Fresh wt./kg Dried wt./kg Loss in wt.

1 7.1 1.5 792 9.2 5.7 383 24.1 13.95 42L. 41.9 19.45 54

17.9 4.95 726 41.9 19.45 547 17.9 4.95 72

Total 93.1 45.55

45

Clupeids with signs of spoilage lose market value by 30%. (e.g.

Naira 1,200 is paid per 50kg bag of freshly dried clupeids whereas

the dull product are sold for Naira 700-800). In the drying process

clupeids may lose up to 79%; of its fresh weight with an average of

51% loss in weight (Table 5.10) due to moisture loss and/or attack

by vermin such as ducks.

Table 5.10 Loss in Weight during Sun Drying of Clupeids

5.6.3 Fish Burning

During the survey, fish burning was observed in Tada Monai. In

the process small fish (50-150g) are packed into dry grass that is

ignited with a smouldering wood. The fish is then burnt for about

15 minutes. After burning they cool in the ash for one hour. The

burnt fish are then transferred to the "Banda" and smoked

overnight.

Tab e 5.11 shows changes in fish weight during the

burning/smoking process. The low weight loss due to burning shows

that burning is not conducted to eliminate moisture per se but to

impart the dark appearance prior to smoking.

Batch No. Fresh wt./kg Dried wt./kg 96 Loss in wt.

1 7.1 1.5 792 9.2 5.7 383 24.1 13.95 424- 41.9 19.45 54

17.9 4.95 726 41.9 19.45 547 17.9 4.95 72

Total 93.1 45.55

46

To some customers the black smoked fish is firmer and will not

disintegrate during cooking. Since the colour of the fish is black

and very unattractive marketing is limited to people who know the

product and who are familiar with the taste.

In comparison to the "normal" smoked fish the burnt product

may be of less nutritional value especially in the available lysine

component because of the high temperature treatment from the

initial burning and subsequent smoking process.

Table 5.11 Loss in Weight During Burning/Smoking of Fish

Fish type Fresh wt. After burning After smoking %Totalwt/kg wt/kg 95wt loss wt/kg %wt loss wt.loss

Assorted 15.64 13.16 15.56 8.55 35.03 51

5.6.4 Fish Frying

Fish fried in groundnut oil is prenared in the markets for

immediate sale to consumers. The fish are washed but not gutted.

They are fried until dry and brittle. The commonest fried fish

during the survey were tilapia and moonfish.

5.7 Fish Marketing - and Marketing Losses

Intensive fish marketing is carried out on market days in

collection centres mainly Yauri, Kokoli, Malale and Warra. Malale

market takes place on Fridays, the others operate every four days.

46

To some customers the black smoked fish is firmer and will not

disintegrate during cooking. Since the colour of the fish is black

and very unattractive marketing is limited to people who know the

product and who are familiar with the taste.

In comparison to the "normal" smoked fish the burnt product

may be of less nutritional value especially in the available lysine

component because of the high temperature treatment from the

initial burning and subsequent smoking process.

Table 5.11 Loss in Weight During Burning/Smoking of Fish

Fish type Fresh wt. After burning After smoking %Totalwt/kg wt/kg %wt loss wt/kg %wt loss wt.loss

Assorted 15.64 13.16 15.56 8.55 35.03 51

5.6.4 Fish Frying

Fish fried in groundnut oil is prenared in the markets for

immediate sale to consumers. The fish are washed but not gutted.

They are fried until dry and brittle. The commonest fried fish

during the survey were tilapia and moonfish.

5.7 Fish Marketing - and Marketing Losses

Intensive fish marketing is carried out on market days in

collection centres mainly Yauri, Kokoli, Malale and Warra. Malale

market takes place on Fridays, the others operate every four days.

47

Fresh fish displayed in these markets are not autted.

Occasionally water is sprinkled over the fresh fish to keep away

flies and to make the fish moist.

They are sold according to species amidst swarms of flies which

might have visited the human excrements in the neighbourhood (since

there are no public toilets available). When fl es remain for a

long time on the fish, they lay eggs and the resultant larvae begin

to eat up the flesh of the fish and hasten its spoilage.

This leads to economic loss to the fish monger as the market value

of the fish is reduced.

To improve the shelf-life of captured fish in the absence of

ice and freezing facilities live table-size fish are also available

for sale in the markets. These live fish are kept in bowls of

water. During the survey for example two Clarotis of about 10kg

each were found curled in a bowl of water awaiting purchase.

Fish meant for smoking are dressed and the entrails and scales

are left carelessly in the market where they attract flies which

transfer bacteria to the fresh and smoked fish displayed for sale.

In the smoked fish section of the market smoked fish are

purchased either directly from the fisherfolk or from the primary

fish sellers. In some market centres, e.g. Yauri there are numerous

small drum type smoking kilns where dried fish from the villages

are re-dried before selling to consumers. Freshly caught fish may

also be dried here and sold the same day to the consumer.

Fish purchased from Kainji Lake basin are distributed to

various places in the country (Annex 11).

47

Fresh fish displayed in these markets are not autted.

Occasionally water is sprinkled over the fresh fish to keep away

flies and to make the fish moist.

They are sold according to species amidst swarms of flies which

might have visited the human excrements in the neighbourhood (since

there are no public toilets available). When flies remain for a

long time on the fish, they lay eggs and the resultant larvae begin

to eat up the flesh of the fish and hasten its spoilage.

This leads to economic loss to the fish monger as the market value

of the fish is reduced.

To imorove the shelf-life of captured fish in the absence of

ice and freezing facilities live table-size fish are also available

for sale in the markets. These live fish are kept in bowls of

water. During the survey for example two Clarotis of about 10kg

each were found curled in a bowl of water awaiting purchase.

Fish meant for smoking are dressed and the entrails and scales

are left carelessly in the market where they attract flies which

transfer bacteria to the fresh and smoked fish displayed for sale.

In the smoked fish section of the market smoked fish are

ourchased either directly from the fisherfolk or from the orimary

fish sellers. In some market centres, e.g. Yauri there are numerous

small drum tyoe smoking kilns where dried fish from the villages

are re-dried before selling to consumers. Freshly caught fish may

also be dried here and sold the same day to the consumer.

Fish purchased from Kainji Lake basin are distributed to

various places in the country (Annex 11).

48

5.7.1 Fish Sellers

Primary fish sellers

This category of fish traders sell fresh or processed fish in

fishing villages and market centres.

For transport and sale they use mainly baskets (49%), basins (29%),

cartons (17%) and bags (5%). The latter are almost entirely used

for dried clupeids.

Almost the whole sample of processed fish was smoked (936),

the rest sun dried.

Before fish were marketed they were stored in fishing villages

at different length of time to enable the fish sellers stock pile

their fish before disposal at the weekly market. (Table 5.12).

Table 5.12 Duration of Storage of Fish by Fish Sellers beforeMarketing

Period (days) No of Respondents

0 3

1- 6 527 - 14 53

> 14 4

Total 112

During the period of storage some fish may undergo spoilage due to

bacterial action on insufficiently smoked fish and insect

infestation of dried fish. Out of the total fish sold by fish

sellers 16% were spoilt. Some primary fish sellers also purchased

fresh fish at the landing site, and after smoking conveyed them in

lorries to Lagos, Abuja, Onitsha and other major towns for sale.

48

5.7.1 Fish Sellers

Primary fish sellers

This category of fish traders sell fresh or processed fish in

fishing villages and market centres.

For transport and sale they use mainly baskets (49%), basins (29%),

cartons (17%) and bags (5%). The latter are almost entirely used

for dried clupeids.

Almost the whole sample of processed fish was smoked (93%),

the rest sun dried.

Before fish were marketed they were stored in fishing villages

at different length of time to enable the fish sellers stock pile

their fish before disposal at the weekly market. (Table 5.12).

Table 5.12 Duration of Storage of Fish by Fish Sellers beforeMarketing

Period (days) No of Respondents

0 3

1- 6 527 - 14 53

> 14 4

Total 112

During the period of storage some fish may undergo spoilage due to

bacterial action on insufficiently smoked fish and insect

infestation of dried fish. Out of the total fish sold by fish

sellers 16% were spoilt. Some primary fish sellers also purchased

fresh fish at the landing site, and after smoking conveyed them in

lorries to Lagos, Abuja, Onitsha and other major towns for sale.

49

Secondary fish sellers

Secondary fish sellers purchase from the primary fish sellers

at collection centres and sell to agents or retailers at local cr

distant markets. These are also fish merchants.

To avoid spoilage during long distant transport the fish is

packed in cartons. The carton bottom is covered with thick brown

paper or dry grasses to seal all crevices and provide a c-shion for

the fish to avoid breakage. When the carton is packed with fish a

mixture of groundnut oil and water is sprinkled (or blown with the

mouth) over the top layer to give the fish a shiny appearance.

An unspecified insecticide, "Otapiapian is sprinkled all over the

fish and the inside of the carton to prevent insect infestation.

The fish is then covered with thick brown paper.

5.7.2 Fish Buyers

Fish buyers are described as those engaged in the purchase of

mainly dried fish from fisherfolks or nrimary fish sellers at the

fishing village or market centres. The fish is either re-sold to

secondary fish sellers or processed.

The fish buyers are different from the secondary fish sellers

who purchased only dried fish, packaged the fish and dispose of

them in distant markets.

Oreochremis nilcticus was the highest in number (62) and in

weiaht (1581.04 kg out of a total of 12,017.27 kg) of fish sampled

at purchasing point, followed by Alestes baremose, Citharinus

citharus, Ciarías anquillaris and clupeids.

49

Secondary fish sellers

Secondary fish sellers purchase from the primary fish sellers

at collection centres and sell to agents or retailers at local or

distant markets. These are also fish merchants.

To avoid spoilage during long distant transport the fish is

packed in cartons. The carton bottom is covered with thick brown

paper or dry grasses to seal all crevices and provide a c-shion for

the fish to avoid breakage. When the carton is packed with fish a

mixture of groundnut oil and water is sprinkled (or blown with the

mouth) over the top layer to give the fish a shiny appearance.

An unspecified insecticide, "Otapiapian is sprinkled all over the

fish and the inside of the carton to prevent insect infestation.

The fish is then covered with thick brown paper.

5.7.2 Fish Buyers

Fish buyers are described as those engaged in the purchase of

mainly dried fish from fisherfolks or nrimary fish sellers at the

fishing village or market centres. The fish is either re-sold to

secondary fish sellers or processed.

The fish buyers are different from the secondary fish sellers

who purchased only dried fish, packaged the fish and dispose of

them in distant markets.

Oreochromis nilcticus was the highest in number (62) and in

weiaht (1581.04 kg out of a total of 12,017.27 kg) of fish sampled

at purchasing point, followed by Alestes baremose, Citharinus

citharus, Ciarías anguillaris and clupeids.

50

The least purchased fish was Synodontis qambiensis. Table 5.13

shows the quantity of fish purchased and the level of losses from

spoilage in each container.

The total spoilage was 6.4% of the weight of fish bought. The

spoilt fish were down-graded and sold at a much lower price to be

used essentially as fish meal in livestock feeds.

5.7.3 Losses Due ta Packaging and Storage

Cartons are commonly used for fish transportation to southern

markets (Proctor, 1977). A field survey (Eyo and Awoyemi, 1990)

revealed that these packages often lead to fragmentation of fish

during the long transportation from the sources to the final

destination. It is estimated that for every 25kg pack of fish about

1.5 kg is lost to fragmentation through rough handling during

transportation.

Apart from the physical loss and down-grading of fish there

may also be an economic loss since broken fish is believed to fetch

lower price than intact products.

Table 5.13 Quantity of Spoilt Fish Purchased by Fish Buyers

Containers Fish purchased Quantity spoilt Percentageno wt/kg no wt/kg no wt

Carton 144 4025 20 569 14 14Basin 139 1124 14 134 10 12Bag 18 1071Basket 219 5794 37 63 17 2

Tray 10 3 3 0.55 30 18

Total 530 12017 74 766 14 6

50

The least purchased fish was Synodontis qambiensis. Table 5.13

shows the quantity of fish purchased and the level of losses from

spoilage in each container.

The total spoilage was 6.4% of the weight of fish bought. The

spoilt fish were down-graded and sold at a much lower price to be

used essentially as fish meal in livestock feeds.

5.7.3 Losses Due to Packaging and Storage

Cartons are commonly used for fish transportation to southern

markets (Proctor, 1977). A field survey (Eyo and Awoyemi, 1990)

revealed that these packages often lead to fragmentation of fish

during the long transportation from the sources to the final

destination. It is estimated that for every 25kg pack of fish about

1.5 kg is lost to fragmentation through rough handling during

transportation.

Apart from the physical loss and down-grading of fish there

may also be an economic loss since broken fish is believed to fetch

lower price than intact products.

Table 5.13 Quantity of Spoilt Fish Purchased by Fish Buyers

Containers Fish purchased Quantity spoilt Percentageno wt/kg no wt/kg no wt

Carton 144 4025 20 569 14 14Basin 139 1124 14 134 10 12Bag 18 1071Basket 219 5794 37 63 17 2

Tray 10 3 3 0.55 30 18

Total 530 12017 74 766 14 6

51

Fragmentation often also encourages pest damage (FAO, 1981) as

fragmented particles are favoured for rapid breeding of insects and

mites.

The unhygienic conditions in mud walled store houses around

Lake Kainji also contribute to fish losses. Packaged fish are often

left on the floor of the stores where they can get humid resulting

in rapid insect infestation and fungal infections that makes the

fish unsightly for marketing. Temperature changes between the fish

directly resting on the bare floor and those in the upper units of

cardboard, jute or basket packages have been observed to vary by as

much as 15°C by Osuji (1974). This temperature variations encourage

infestation by beetle pests and often lead to serious loss of fish

quality in storage.

5.7.4 Losses Due to Insect and Mite Infestation

Insects.and mites are often found infesting cured fish during

and after processing. Quantitative losses of cured fish have been

reported to be up to 3(A due to fly damage and up to 5096' due to

beetle damage during processing (Haines 1984). Examples of world

wide losses of dried fish due to insect infestation are given by

Poulter et al, (1989). James (1977) estimated the world production

of dried fish at approximately 12 million tonnes annually out of

which 3 millions tonnes are lost due to insect pest infestation.

51

Fragmentation often also encourages pest damage (FAO, 1981) as

fragmented particles are favoured for rapid breeding of insects and

mites.

The unhygienic conditions in mud walled store houses around

Lake Kainji also contribute to fish losses. Packaged fish are often

left on the floor of the stores where they can get humid resulting

in rapid insect infestation and fungal infections that makes the

fish unsightly for marketing. Temperature changes between the fish

directly resting on the bare floor and those in the upper units of

cardboard, jute or basket packages have been observed to vary by as

much as 15°C by Osuji (1974). This temperature variations encourage

infestation by beetle pests and often lead to serious loss of fish

quality in storage.

5.7.4 Losses Due to Insect and Mite Infestation

Insects.and mites are often found infesting cured fish during

and after processing. Quantitative losses of cured fish have been

reported to be up to 30% due to fly damage and up to 50% due to

beetle damage during processing (Haines 1984). Examples of world

wide losses of dried fish due to insect infestation are given by

Pouirer et al, (1989). James (1977) estimated the world production

of dried fish at approximately 12 million tonnes annually out of

which 3 millions tonnes are lost due to insect pest infestation.

52

Araf et al, (1964) estimated weight losses of dried fish due to

Dermestes sp. (Coleoptera) infestation at about 50%, Rollings and

Hayward (1963) estimated such losses at Lake Chad at 50% while che

FAO (1981) suggested losses of 25-30% as being typical in Burkina

Faso and Mali.

In the Kainji Lake area, Awoyemi (1988) estimated dried fish

weight losses due to Dermestes sp. damage in a 6-month storage

period at 26-34%. The hurry to get improlDerly dried fish to market

increases the susceptibility' of processed fish to blowfly

infestat:on and also beetle infestation in storage. The

indiscriminate method of mixing wet fish with properly dried ones

particularly as observed among fish mongers at Doro-Malale, Yauri

and Shaaunu markets encourages cross infestation of fish being

packaged for distant consumer markets. Consequently products are

moved into storage with a high level of infestation.

The prevailing warmth in the storage environment encourages

rapid development of the eggs to larvae which are the most

destructive stages of stored dried fish. Within few weeks most of

the infested fish could be reduced to frass and bones. The

contamination of few surviving whole fish by live or dead pests or

their cast skins and excreta also causes a change in visual quality

and this may reduce the value of the fish.

Lardoglyphid mites occur on dried fish at various stages in

storage and marketing especially during the cool wet season. Insect

and mite pests often transmit mould spores.

52

Araf et al, (1964) estimated weight losses of dried fish due to

Dermestes sp. (Coieoptera) infestation at about 50%, Railings and

Hayward (1963) estimated such losses at Lake Chad at 50% while the

FAO (1981) suggested losses of 25-30% as being typical in Burkina

Faso and Malí.

In the Kainji Lake area, Awoyemi (1988) estimated dried fish

weight losses due to Dermestes sp. damage in a 6-month storage

period at 26-34%. The hurry to get improlDerly dried fish to market

increases the susceptibility' of processed fish to blowfly

infestation and also beetle infestation in storage. The

indiscriminate method of mixing wet fish with properly dried ones

particularly as observed among fish mongers at Doro-Malale, Yauri

and Shaaunu markets encourages cross infestation of fish being

packaged for distant consumer markets. Consequently products are

moved into storage with a high level of infestation.

The prevailing warmth in the storage environment encourages

rapid development of the eggs to larvae which are the most

destructive stages of stored dried fish. Within few weeks most of

the infested fish could be reduced to frass and bones. The

contamination of few surviving whole fish by live or dead pests or

their cast skins and excreta also causes a change in visual quality

and this may reduce the value of the fish.

Lardoglyphid mites occur on dried fish at various stages in

storage and marketing especially during the cool wet season. Insect

and mite pests often transmit mould spores.

53

This in addition can create conditions suitable for fungal growth

on fish that have previously been dried but indiscriminately

packaged with infested ones.

The principal effect of all these activities is the imparting

of an unsavoury odour to the commodities and reduction in their

aesthetic appeal to consumers.

5.7.5 Situation in Onitsha Market

Onitsha (Osa) market was chosen out of the several bigger town

market places in Nigeria that trade fish from Kainji Lake. As a

routine the lorries conveying the fish sellers and dried fish from

Kainji area arrive at the market on Sundays. The following morning

the fish are sold directly from the lorries to the fish retailers

(mainly women) via the commissioned agents who are from the

Northern Part of the country. The retailers have their customers

amona the fish sellers-and when the cartons are dropped they are

opened for quality assessment prior to purchasing. A carton of big

sized Clarotis might go for between Naira 8,000 - 12,000 while

small size fish such as Synodontis and small Lates and Labeo are

sold for Naira 4,000 per carton. Up to 500 pieces of fish weighing

about 60 kg was found in each carton. A commission ranging be ween

Naira 1 - 3 per fish is charged by the fish retailers.

During the glut season when the fish brought to the market are

not sold out the same day, such fish are usually stored in a ware

house to be sold during the week. The money realised is given to

the fish merchants whenever they return with the next supply.

53

This in addition can create conditions suitable for fungal growth

on fish that have previously been dried but indiscriminately

packaged with infested ones.

The principal effect of all these activities is the imparting

of an unsavoury odour to the commodities and reduction in their

aesthetic appeal to consumers.

5.7.5 Situation in Onitsha Market

Onitsha (Osa) market was chosen out of the several bigger town

market places in Nigeria that trade fish from Kainji Lake. As a

routine the lorries conveying the fish sellers and dried fish from

Kainji area arrive at the market on Sundays. The following morning

the fish are sold directly from the lorries to the fish retailers

(mainly women) via the commissioned agents who are from the

Northern part of the country. The retailers have their customers

among the fish sellers-and when the cartons are dropped they are

opened for quality assessment prior to purchasing. A carton of big

sized Clarotis might go for between Naira 8,000 - 12,000 while

small size fish such as Svnodontis and small Lates and Labeo are

sold for Naira 4,000 per carton. Up to 500 pieces of fish weighing

about 60 kg was found in each carton. A commission ranging be ween

Naira 1 - 3 per fish is charged by the fish retailers.

During the glut season when the fish brought to the market are

not sold out the same day, such fish are usually stored in a ware

house to be sold during the week. The money realised is given to

the fish merchants whenever they return with the next supply.

54

A few of the fish retailers in Onitsha market cut the fish

into small pieces and display on table tops. These fish were sold

at the same price as the intact ones which suggest that dried

broken fish may not necessarily lead to econcmic loss as widely

assumed (see above). Apparently when fish are displayed in broken

forms consumers are able to see the flesh and assess the quality

before paying for it.

Losses of dried fish at Onitsha market was estimated at 56

mainly due to fragmentation resulting from insufficient smoking.

Incident of insect attack was very minimal. This was attributed to

the effect of the pesticide "Otapiapian (see above).

6. CONCLUS ION AND RECOMMENDATIONS

Based on the 1995 fish yield for Kainji lake fishery estimated

at 14,000t, approximately 1,000t of fish estimated at N 80m was

lost during handling by fisherfolks. This figure is much higher if

the subsequent marketing losses are included.

With the increasingly low domestic fish production in Nigeria,

any management strategy for Kainji Lake fishery must include

improvement in the existing traditional handling, preservation/

processing and marketing practices in the lake basin in order to

make the much desired impact on fish availability.

The following recommendations are given to significantly

reduce losses in the Kainji lake fishery:

54

A few of the fish retailers in Onitsha market cut the fish

into small pieces and display on table tops. These fish were sold

at the same price as the intact ones which suggest that dried

broken fish may not necessarily lead to economic loss as widely

assumed (see above). Apparently when fish are displayed in broken

forms consumers are able to see the flesh and assess the quality

before paying for it.

Losses of dried fish at Onitsha market was estimated at 56

mainly due to fragmentation resulting from insufficient smoking.

Incident of insect attack was very minimal. This was attributed to

the effect of the pesticide "Otapiapia" (see above).

6. CONCLUS ION AND RECOMMENDATIONS

Based on the 1995 fish yield for Kainji lake fishery estimated

at 14,000t, approximately 1,000t of fish estimated at N 80m was

lost during handling by fisherfolks. This figure is much higher if

the subsequent marketing losses are included.

With the increasingly low domestic fish production in Nigeria,

any management strategy for Kainji Lake fishery must include

improvement in the existing traditional handling, preservation/

processing and marketing practices in the lake basin in order to

make the much desired impact on fish availability.

The following recommendations are given to significantly

reduce losses in the Kainji lake fishery:

55

1 Fishing time with the available fishing gears should be

reduced to the barest minimum and should not exceed 12 hours

prior to checking. This will enable most of the fish caught

early to remain in excellent condition at checking.

2 Spoilage is faster with small fishes than big matured ones

therefore the use of small mesh sizes in gill nets which

catches mainly small fishes should be restricted. The

minimum stretched mesh size of 76mm or 3" as stipulated in

the Inland Fisheries Degree of 1992 should be enforced on

the lake by the appropriate authority.

Fish should be handled properly on board by gutting, washing

and storing in clean boxes or containers. Raffia mats should

be used co shade the fish in containers or the fish may be

wrapped in wet jute bags to facilitate evaporative cooling

during the long trip to the shore.

The popular smoking kiln on the Lake basin "Banda" is not

economical in the use of fuel wood because of its design

being restricted to only one tray. The Chorkor oven is

recommended for fish smoking at the Kainji Lake basin as it

can handle far more fishes than the "Banda" kiln and is more

fuel efficient.

Fisherfolks should be encouraged to cultivate firewood as

cash crops in the lake basin to combat the current scarcity

and high ccst of firewood. There appear to be no alternative

to the use of wood for traditional smoking at the moment.

55

1 Fishing time with the available fishing gears should be

reduced to the barest minimum and should not exceed 12 hours

prior to checking. This will enable most of the fish caught

early to remain in excellent condition at checking.

2 Spoilage is faster with small fishes than big matured ones

therefore the use of small mesh sizes in gill nets which

catches mainly small fishes should be restricted. The

minimum stretched mesh size of 76mm or 3" as stipulated in

the Inland Fisheries Degree of 1992 should be enforced on

the lake by the appropriate authority.

Fish should be handled properly on board by gutting, washing

and storing in clean boxes or containers. Raffia mats should

be used co shade the fish in containers or the fish may be

wrapped in wet jute bags to facilitate evaporative cooling

during the long trip to the shore.

The popular smoking kiln on the Lake basin "Banda" is not

economical in the use of fuel wood because of its design

being restricted to only one tray. The Chorkor oven is

recommended for fish smoking at the Kainji Lake basin as it

can handle far more fishes than the "Banda" kiln and is more

fuel efficient.

Fisherfolks should be encouraged to cultivate firewood as

cash crops in the lake basin to combat the current scarcity

and high cost of firewood. There appear to be no alternative

to the use of wood for traditional smoking at the moment.

56

Fish stalls should be established for the storage of dried

fish in each of the collection centres. The existing ones

should be refurbished to make them useable.

Appropriate sheds, toilets, wells and incinerators should be

provided in each of the collection centres to facilitate

proper waste disposal and improve hygiene in these centres.

This will reduce cross infestation of fish by flies and

beetles.

Clupeids should be sun-dried on racks to hasten the drying

process and reduce bacteria infestation and attack by vermin

and domestic animals.

Access to fish markets should be improved by grading the

existing latente roads regularly to make them motorable and

opening good road network where this does not exist.

There should be training of fisherfolks on proper methods of

fish handling, processing and marketing.

The expert can co-ordinate such a training which will

significantly reduce fish spoilage on the lake.

It is suggested that the Nigerian standard Organisation (NSO)

should be informed on the wanton use of the pesticide

"Otapiapia" and other toxic chemicals on smoked fish. NSO

should conduct analysis of the chemicals and determine the

active ingredients. The spurious claims by manufacturers of

these obviously toxic pesticides that they are harmless to

man (as displayed on the labels) is questionable.

56

Fish stalls should be established for the storage of dried

fish in each of the collection centres. The existing ones

should be refurbished to make them useable.

Appropriate sheds, toilets, wells and incinerators should be

provided in each of the collection centres to facilitate

proper waste disposal and improve hygiene in these centres.

This will reduce cross infestation of fish by flies and

beetles.

Clupeids should be sun-dried on racks to hasten the drying

process and reduce bacteria infestation and attack by vermin

and domestic animals.

Access to fish markets should be improved by grading the

existing latente roads regularly to make them motorable and

opening good road network where this does not exist.

There should be training of fisherfolks on proper methods of

fish handling, processing and marketing.

The expert can co-ordinate such a training which will

significantly reduce fish spoilage on the lake.

It is suggested that the Nigerian standard Organisation (NSO)

should be informed on the wanton use of the pesticide

"Otapiapia" and other toxic chemicals on smoked fish. NSO

should conduct analysis of the chemicals and determine the

active ingredients. The spurious claims by manufacturers of

these obviously toxic pesticides that they are harmless to

man (as displayed on the labels) is questionable.

57

12. The use of pesticides is not often recommended because of the

possibility of misuse by uneducated and untrained fisherfolks

and fish traders. But since these fish handlers are now used

to pesticide application on dried fish, they should be

introduced to the use of approved pesticides. The only

pesticide approved for use in dried fish is actellic

containing the active ingredient Pirimiphos methyl. It is

recommended that this pesticide be provided at collection

centres for the fish traders to buy and they should also be

trained on the proper application of this pesticide on dried

fish.

57

12. The use of pesticides is not often recommended because of the

possibility of misuse by uneducated and untrained fisherfolks

and fish traders. But since these fish handlers are now used

to pesticide application on dried fish, they should be

introduced to the use of approved pesticides. The only

pesticide approved for use in dried fish is actellic

containing the active ingredient Pirimiphos methyl. It is

recommended that this pesticide be provided at collection

centres for the fish traders to buy and they should also be

trained on the proper application of this pesticide on dried

fish.

58

ANNEXIRIGOR MORTIS

The term rigor mortis is used to describe the stiffness in

fish muscle after death.

Immediately the fish dies the muscles are soft and limp and

can easily be flexed, the fish is said to be in pre-rigor stage.

After a short time the muscles begin to stiffen and becomes so hard

that they cannot be flexed easily. This is the rigor stage which

may last for some minutes or hours depending on certain factors. At

the end of rigor the muscles become soft and limp once more and

this stage is known as the post-rigor phase. Rigor in fish usually

starts from the tail and gradually move to the body and the head

until the entire fish becomes rigid. The duration and subsequent

resolution of rigor depends on many factors such as species, size,

catching method, handling of the fish, temperature and physical

condition of the fish (Huss, 1988).

58

ANNEX1RIGOR MORTIS

The term riaor mortis is used to describe the stiffness in

fish muscle after death.

Immediately the fish dies the muscles are soft and limp and

can easily be flexed, the fish is said to be in pre-rigor stage.

After a short time the muscles begin to stiffen and becomes so hard

that they cannot be flexed easily. This is the rigor stage which

may last for some minutes or hours dependLng on certain factors. At

the end of rigor the muscles become soft and limp once more and

this stage is known as the post-rigor phase. Rigor in fish usually

starts from the tail and gradually move to the body and the head

until the entire fish becomes rigid. The duration and subsequent

resolution of rigor depends on many factors such as species, size,

catching method, handling of the fish, temperature and physical

condition of the fish (Huss, 1988).

59

ANNEX2DIS1RIBUTION OF RESPONDENTS IN FISHING VILLAGES PD CENTRES

Collection FishingCentres Villages

=MA FADAANGWAN SAL KAWAYABOGUNGUN SARKI

7

3

1

21

4 5

INAN BIROYELWA 12 27 45BUNZAWA 10

4ALALE TUNGAN ISAMIYA 2 3

TUNGAN SULE 6 4 53 3

GUNGUN DORINA 1

TUNSAN DORINAMALALE 25 6 28

"LARA KUKA UKU 1 1

TETEKU 5

KWANGA 2

UNGWAN HALIDU 2

WARA 65 7 25 26

TUNA TUNGAN ALHAJI-DAN BABA 1 2

YUNAWA 1 7

TADA 1

WADATA 5 5

MONAI 9 3

YUNA 2

KURUWASA 23 4

TUGAN LEDA 6 1

SHAGUNU AMBOSHIDI 1

TUNGAN BALA 19UMARU MAISAGE 1

TUNGAN DOGO 2 1

SHAGUNU 9 12WAWU WAWU 42 2

Handling Processing Marketing MarketingLosses Losses Losses Losses

Buyer Seller

59

ANNEX2DISTRIBUTION OF RESPONDENTS IN FISHING VILLAGES AND CENTRES

fELWA FADAANGWAN SAL KAWAYABOGUNGUN SARKIINAN BIRO

73

1

21

4 5

YELWA 12 27 45BUNZAWA 10

4ALALE TUNGAN ISAMIYA 2 3

TUNGAN SULE 6 4 53 3

GUNGUN DORINA 1

TUNSAN DORINAMALALE 25 6 28

ATARA KUKA UKU 1 1TETEKU 5

KWANGA 2

UNGWAN HALIDU 2

WARA 65 7 25 26

ZUNA TUNGAN ALHAJI-DAN BABA 1 2

YUNAWA 1 7

TADA 1

WADATA 5 5

MONAI 9 3

YUNA 2

KURUWASA 23 4

TUGAN LEDA 6 1

SHAGUNU AMBOSHIDI 1

TUNGAN BALA 19UMARU MAISAGE 1

TUNGAN DOGO 2 1

SHAGUNU 9 12WAWU WAWU 42 2

Collection Fishing Handling Processing Marketing MarketingCentres Villages Losses Losses Losses Losses

Buyer Seller

Table continues

60

FOGE ISLAND 12 18

TOTAL 314 115 125 111

Collection Fishing Handling Processing Marketing MarketingCentres Villages Losses Losses Losses Losses

Buyer Seller

WAWU JAJI 9

CHAPMANI 2

KOKOLI TUNGAN ROGO 1

TUNGAN DUTCE 2

TUNGAN AHMADUKOKOLI 5 1

AMPHANI GADAN SARETUNGAN GORAKENDAWA 6

TUNGAN GARI 1

AMFANI 24 2

BARKIN DAM 15 7

GUNGAWA 1

Table continues

60

FOGE ISLAND 12 18

TOTAL 314 115 125 111

Collection Fishing Handling Processing Marketing MarketingCentres Villages Losses Losses Losses Losses

Buyer Seller

WAWU JAJI 9

CHAPMANI 2

KOKOLI TUNGAN ROGO 1

TUNGAN DUTCE 2

TUNGAN AHMADUKOKOLI 5 1

AMPHANI GADAN SARETUNGAN GORAKENDAWA 6

TUNGAN GARI 1

AMFANI 24 2

BARKIN DAM 15 7

GUNGAWA 1

61

ANNEX3MAP OF THE STUDY AREA

-10.30 N

Kainji Lake, Northern Nigeria.Showing the distribution of fishing villages

Uoy .9111: Olgaclani .0.4.1,11 LAMob.. 0006.1.

O. gos TOS, N. 44.1.Olgar State, Dig..

KAINJI Maldugurt°Kano,.

NIGERIA1 LA006

North

1nka

t ao- e/_--I oug. T. A.. 044

0t 11+N.

Golagun Da. :.:1

I

1Olora.

Talawa

gango

AArla

11144,zataar..4J.4.it=Diaganaa.

I 1, 1441 akTata.

naal-- ...a. Aorl Agog.* -I V. WOW& 11114.4 I -T.. Mmal I 1 7.."... It".. "-

..9.1,11 7 AwataoL... mtmm -

Aogo

cao.aso.4n2 IlakLA1

,1121.a.a.a.

U11114.244

gAgIare

Can.

DAM1Daga .1.4 01.Ouga

TwouToo. Al.)1Ton.... goo. Lo. %TT

LIOSO

runga .daD.G. D.- Aoaa ntala

Tang 71.Dali.Tung Oman 1,4aarLo.

'1X11=414,1A11.J1 Nano

sung. L44-4

Shsrunu

nuaga Dogo

1100.0101 1T. DA.

lotta11..WA. Dal..

Tugga

Sat.io tAsoalaj

)1.41.91 2

124.11..41DA

OM 111.0r

441212.10.11a. Di..AGAgga

00.10.

Updated 30/T2/98

SaldgT gul .Gado

Bs. Maya "115.` N.1Io

T. Gad, 14.1124..ga0111 Sagoro

gala1.4.14

4.30W ram!.

0.4

YArti,1:21:7"a.

EIV

gt,Aim

T.G.14611 Tun...11 S...T. P.4412

.. ...A 71ffer.r.1).1.

D.A ---rÇID. oat/. AllyoT. 11.101..u.

040,T. All.0Gogo 1121.T. Agal.

tof1 Two

0. Lavaha

LTIrtlT. Magawa

T.

.1. ALA 0444441 -

04.01111 Walc%Tado

.ata -Ora. o..414 goo 1S42112 atoo 2

0.1.4Mmra

XIDna

TA.

0. AID. gharm

goo.

ItoT.

=7:""' 4r:2.14.

pli ix1.vaaahj,,p1.141.D.wa 0/

.11b011

tAlgogo Dag.Tung

Wsza-T. 1441..tann

t442141 HAW. Ino.gsg. Toss.Gy.a

0. MA. 1124.1A

1Mam

14..4DAt

GadAAT00,0 LID04O.AorantBiJi4 Oa lat,34.1. Glga

Anoo1a.

Lindar.00.1

.1111.Pit

61

ANNEX3MAP OF THE STUDY AREA

- 10.30 N

KAINJI Maldugurt.)<Ano.

NIGERIA1 LAO06

North

.2....Kum.

I."4''0''". 01.iAg:

I ()"T".2....

Tota.lni10.2212 TI1'-... W.I. /6.1 /Napo. -. I. ----- 1.22,...i V. KAM. 11.2222. I --iiTun. I..I 1 .7.... A... 2/ -0 J ..T k fa....-

0.1.00.0. ¡;p2do T. W.. -

TalS.

Nalsott7

su-e,,,L_Burawa

ouo T. MI,

epty ript: sigguara 0100kA MIMi LAM11...2. Militia frOJMt.2 O. Ms 306, H.

14.14soT. iharu

I.12Cu. Ol.,

2.11. 1.2221Yuma12202

Tunis 2.11222.2.. 'Mtn'rung. Kaa.24 .

VS.. 0.- Ama71.

G1.1.11. 112.2m.Turt. Um. 3.22122.

212. sm.

Ttaup MI.)/ Yu.TIMM

Stuxstunu

lung* pogo

Ambovh/01. 1

T. 1142.Dup.Ma. 1.240.241,T.. M.

21250, ta..1s.12.1.222 2

etan.212../y2

1111941

2.21rattml2.11...

Waal.anuo

Updated 30/T2/98

MUM M..SuL _Ga. N,

NOMIT

T. Mr. Msallv.ktlt tutor*

T.

tWToarolSarloT. M0.10T. P...12T.13.4.113

22.70

T.

T. 11.1.02.2

T, balu.1

11.0.

ft312 VittOibi-

T. .1y21242Irel

22F%letCw. M. 2

1

.2.122 22. 2

0.4.241d

Tun. 12.31 Intars

77/3!--r9.1.1.11Dartirf/OWN"

U 1.550

T. Ms. 22121.

"=7:.=:1.1

/

Tun. 02.4.12.02.22221.2.

/*It iXS. 1.41:4

7.2212. II

totiaugu Tag.Dingo 51.21

liaca- T. UM..ta'aPtT t144 .2.22.

Tuns.MiaLy.a

O.. T.. T. MA. I...T. MI.0.1.T. 0.212.

rigialTa

zzinVii

SC'11.1 T.Ta BtaT. rupawa Gad. W.rm.,. Kt...

Mfr./6.14 OM.Su.Uuu 4221a2.721,AnTula1,i4TWA12112daMDotal

en

Kainji Lake, Northern Nigeria.Showing the distribution of fishing villages

4. 30 W

REMARKS:

62

ANNEX4

QUESTIONNAIRES

QUESTIONNAIRE ON HANDLING LOSSES

STATION-

TIME OF LANDING

NAME FISHERMAN

GEAR

SPECIES CAUGHT

SPECIE SPOILT/

DISCARDED WHILE

CHECKING

SPECIE SPOILT/

DISCARDED AT

LANDING

SPECIE

NO

WT

SPECIE

NO

WT

SPECIE

NO

WT

'

DAY I DATE:

DAY 2 DATE:

TIME OF SETTING-

TIME OF CHECKING.

REMARKS:

62

ANNEX4

QUESTIONNAIRES

QUESTIONNAIRE ON HANDLING LOSSES

STATION-

TIME OF LANDING

NAME FISHERMAN

GEAR

SPECIES CAUGHT

SPECIE SPOILT/

DISCARDED WHILE

CHECKING

SPECIE SPOILT/

DISCARDED AT

LANDING

SPECIE

NO

WT

SPECIE

NO

WT

SPECIE

NO

WT

DAY I DATE.

DAY 2 DATE.

TIME OF SETTING-

TIME OF CHECKING-

63

QUESTIONNAIRE ON PROCESSING LOSSES

STATION-

NAME OF PROCESSOR

METHOD

PROCESSING

QUANTITY OF FISH BOUGHT FROM

CUSTOMER

QUANTITY OF FISH

SPOILT/DISCARDED

BEFORE PROCESSING

QUANTITY OF FISH

SPOILT/DISCARDED

AFTER PROCESSING

SPECIE

NO

BASIN

WT

SPECIE

NO

WT

SPECIE

NO

WT

REMARKS

63

QUESTIONNAIRE ON PROCESSING LOSSES

STATION-

NAME OF PROCESSOR

METHOD

PROCESSING

QUANTITY OF FISH BOUGHT FROM

CUSTOMER

QUANTITY OF FISH

SPOILT/DISCARDED

BEFORE PROCESSING

QUANTITY OF FISH

SPOILT/DISCARDED

AFTER PROCESSING

SPECIE

NO

BASIN

WT

SPECIE

NO

WT

SPECIE

NO

WT

REMARKS

64

QUESTIONNAIRE ON MARKETING LOSSES (1) SELLER

STATION-

REMARKS

NAME OF FISH

SELLER

PLACE FISH

OBTAINED

NATURE

OF FISH

DUTATION OF

STORAGE BEFORE

MARKETING

QUANTITY

OF FISH

MARKETED

QUANTITY OF

FISH SPOILT/

DISCARDED

METHOD OF

PACKAGING

CAUSED OF

SPOILAGE

No

Wt

No

Wt

Basket,carton,basin

64

QUESTIONNAIRE ON MARKETING LOSSES (1) SELLER

STATION-

REMARKS

NAME OF FISH

SELLER

PLACE FISH

OBTAINED

NATURE

OF FISH

DUTATION OF

STORAGE BEFORE

MARKETING

QUANTITY

OF FISH

MARKETED

QUANTITY OF

FISH SPOILT/

DISCARDED

METHOD OF

PACKAGING

CAUSED OF

SPOILAGE

No

Wt

No

Wt

Basket,carton,basin

REMARKS

65

QUESTIONNAIRE ON MARKETING LOSSES (2) BUYER

STATION.

NAME FISH

BUYER/

DISTRIBUTOR

PLACE OF

DISPOSAL

TIME B/W

PURCHASE

DISPOSOL

QUANTITY OF FISH

PURCHASED

QUANTITY OF FISH

SPOILT/DISCARDED

ALTERNATIVE USE

FOR THE DISCARDED

FISH

ADDITIONAL

PROCESSING

SPECIE

CARTON Wt

SPECIE

CARTON Wt

SEASON ANIMAL SPECIE

REMARKS

65

QUESTIONNAIRE ON MARKETING LOSSES (2) BUYER

STATION-

NAME FISH

BUYER/

DISTRIBUTOR

PLACE OF

DISPOSAL

TIME B/W

PURCHASE

DISPOSOL

QUANTITY OF FISH

PURCHASED

QUANTITY OF FISH

SPOILT/DISCARDED

ALTERNATIVE USE

FOR THE DISCARDED

FISH

ADDITIONAL

PROCESSING

SPECIE

CARTON Wt

SPECIE

CARTON Wt

SEASON ANIMAL SPECIE

ANNEX 5

Quality Scores and Organoleptic Changes for Moonfish

Cith

arin

us c

ithar

us -

Raw samples.

66

Score

Eyes

Gills

Skin

Flesh

Grade

10.

Convex

Bright red

Bright grey at

Firm,tender

1-1st Quality

iridescent

fresh odour

dorsal region

silvery ventral

8Convex loss

Pale red,

Pale grey dorsal,

Less firm.

2-2nd Quality

of brightness

fresh odour

silvery ventral.

Scales firm.

6Convex

Pinkish neutral

Pale grey dorsal

Neither firm

3-3rd Quality

cloudy

odour

cream colour

nor soft.

ventral.

Scales firm.

4Flat

Bleached Neutral Pale grey dorsal

Soft

Limit of

Dark Cream

ventral some

accepta-

loose scales

bility

2Slightly

Bleached very

Pale grey dorsal

Very soft

Rejected

sunken

sour

leaves finger

indentation

0Very sunken

Greenish

Pale grey dorsal

Very soft and

Rejected

or concave

ammoniacal

Greenish ventral

flabby

scales completely

loose.

ANNEX 5

Quality Scores and Organoleptic Changes for Moonfish

Cith

arin

us c

ithar

us -

Raw samples.

66

Score

Eyes

Gills

Skin

Flesh

Grade

10.

Convex

Bright red

Bright grey at

Firm,tender

1-1st Quality

iridescent

fresh odour

dorsal region

silvery ventral

8Convex loss

Pale red,

Pale grey dorsal,

Less firm.

2-2nd Quality

of brightness

fresh odour

silvery ventral.

Scales firm.

6Convex

Pinkish neutral

Pale grey dorsal

Neither firm

3-3rd Quality

cloudy

odour

cream colour

nor soft.

ventral.

Scales firm.

4Flat

Bleached Neutral Pale grey dorsal

Soft

Limit of

Dark Cream

ventral some

accepta-

loose scales

bility

2Slightly

Bleached very

Pale grey dorsal

Very soft

Rejected

sunken

sour

leaves finger

indentation

0Very sunken

Greenish

Pale grey dorsal

Very soft and

Rejected

or concave

ammoniacal

Greenish ventral

flabby

scales completely

loose.

4.

Slightly concave

Bleached, Sour/

Dark grey dorsal

Soft,slightly

Limit of

white pupil,grey

Rancid

silvery ventral

Elastic

acceptability

cornea

67 ANNEX6

Quality scores and organoleptic changes for Trunk fish Mormyrus rume -

Raw samples.

Score

Eyes

Gills

Skin

Flesh

Grade

10.

Convex

Dark Red,

Dark grey dorsal,

Firm,elastic,

1-1st Quality

Dark pupil

fresh odour

silvery ventral

white cornea,

irides-cent

2Concave,

Pale greenish

.Dark grey dorsal

Very soft

Rejected

white pupil

very sour/rancid

creamy ventral

No Elasticity

grey cornea

oConcave,

Greenish/

Dark grey dorsal,

Very soft and

Rejected

white pupil

strong rancid

creamy ventral,

flabby

grey cornea.

8Convex

Pale red,

Dark grey dorsal,

Less firm.elastic

2-2nd Quality

Dark pupil

fresh odour

silvery ventral

white loss of

Bright-ness.

6Flat white pupil

Pinkish sour/

Dark grey dorsal

Less firm,

3-3rd Quality

and cornea

slightly rancid

ventral

slightly elastic

6Flat white pupil

Pinkish sour/

Dark grey dorsal

Less firm,

3-3rd Quality

and cornea

slightly rancid

ventral

slightly elastic

4.

Slightly concave

Bleached, Sour/

Dark grey dorsal

Soft,slightly

Limit of

white pupil,grey

Rancid

silvery ventral

Elastic

acceptability

cornea

67 ANNEX6

Quality scores and organoleptic changes for Trunk fish

Mor

myr

us r

ume

-Raw samples.

Score

Eyes

Gills

Skin

Flesh

Grade

10.

Convex

Dark Red,

Dark grey dorsal,

Firm,elastic,

1-1st Quality

Dark pupil

fresh odour

silvery ventral

white cornea,

irides-cent

2Concave,

Pale greenish

.Dark grey dorsal

Very soft

Rejected

white pupil

very sour/rancid

creamy ventral

No Elasticity

grey cornea

oConcave,

Greenish/

Dark grey dorsal,

Very soft and

Rejected

white pupil

strong rancid

creamy ventral,

flabby

grey cornea.

8Convex

Pale red,

Dark grey dorsal,

Less firm.elastic

2-2nd Quality

Dark pupil

fresh odour

silvery ventral

white loss of

Bright-ness.

SIERRATHRISSA LEONENSISALESIES BAREMOSEALESTES DENTEXALESTES NURSEALESIES MACROLEMOTUSHYDROCYNUS FORSKAHLItHYDROCYNUSBREV1SCITHARINUS CITHARUSDISTICHODUS ROSTRATUSLABE° PSEUDOCOUBIE:LABE° COU13IELABEO:SENEGALENSISSYNODONTIS CLAR1USSYNODONTIS SCHALLSYNODONTIS MEMBRANACEUS'SYNODONTIS:GAMBIENSISSAROTHERODON GALILAEUSOREOCHROMIS NMOTICUS

ILAPIAZILLI:,.MORMYRUS:RUMESCITELBE MYSTUSEUTROP1US NMOTICUSAUCHBNOGLANIS'OCCIDENTALIS

:BAGRUSDOCMACBAGRUS BAYADCPaYSICHTHYS N1GRODITATUSCHRYSICHTHYS AURATUSCLARO 1iS LATICEPSPEETEROBRANCHUS B1DORSALISCLARIUS ANGUELLARISLATES N.ILOTICUS,GYMNARCIIUS NILOTICUS

i hROTIS NILOTICUSSYNODONTIS N1GRITAPOLYPTERUS ENDLICHER1AUCHENOGLANISBISCUTATUSMORMYROPS DELICIOSUSHYPEROPISUS BEBE OCCDENTALISMARCUSEN1US ISIDOR

LAPTERURUS ELECTRICUSSYNODONTIS FFLAMENTOSUSDISTICHODUS BREVIPPINISPETROCEPHAUS BANE

68

ANNEX 7FISH CATCHES BY SPECIES

24839 2389.30

35.30 1.48985 3.97 75.14 3.14

3 0.01 0.10 0 051089 438 23,88 0,10

67 0.27 4.54 0.1972 0.29 13.00 0.5411 004 765 0 32

608: 245 193,70 8,112209 8.89 133.44 5.58

8 0.03 10.25 0.43254 I 02 40:55. 1 70.

14.58 5 86 159:63: 6,68'30 0.12 3.21 0.13

2743 11.04 124.42 5.21883 3 55 164 12. :6 87..

36 014 2.40 :0 1063 0.25 3.10 0.13

6565 26.43 357.27 14.95187 0 75 3:69 0.15112 0.4:5 13.67161 0.65 4.68 0.20

0.51127 5.32 0.22521 210 65 33 273:44 018 13 . 0,54

294 1.18 134.50 5.631117 4.50 126.61 5.301466. 5.90 84.59 354226 0.91 22.10 0.92:

3 0.01 14.50 0.61729 2.93 157.79 6.60

6.3 3 88 210.31 8 80:5.... .0.02 1.20 0.05

49 0.20 51.43 2.15784 3.16 28.20 1.1859 0 24 10 55 0.44

302 22 24,12 1:01..22 0.09 9.80 0.41

163 0.66 27.20 1.141.13 045 10.95 04633 0:13 ,,,, 7.25 0,3054 0.22 2.72 0.11

157 0.63 4.84 0.2066 027 326 014

SIERRATHRIS SA LEONENSISALES TES BAREMOSEALESTES DENTEXALESTES NURSEALESTES MACROLEMOTUSHYDROCYNUS FORSKAHLIIHYDROCYNUS BREWSCITHARINU:S CrITIARUSDISTICHODUS ROSTRATUSLABEO PSEUDOCOUBFELABEO'CQUBIELABEO .SENEGALENSISSYNODONTIS CLARIUSSYNODONTIS SCHALL

.:.SYNODONTIS NIEWRANACEUS"SYNO.DONTIS.:GAMBIENSISSAROTHERODON GALILAEUS

68

ANNE X 7

FISH CATCHES BY SPECIES

OREOCHROMIS NILOTICUS 6565 26.43 357.27 14.95IlLAPIA.ZILLI: 187 0,75 3:69 0.15MORMYRUS:RUME /12 0.45 13:67 0,57SCITELBE MYSTUS 161 0.65 4.68 0.20EUTROPIUS NELOTICUS 127 0.51 5.32 0.22AUCHENOGLANIS OCCIDENTALIS 521 2,10 65 33 273

:13AGRUS DOCMAC 44 0 18 13 0,54BAGRUS BAYAD 294 1.18 134.50 5.63CHRYSICHTHYS NIGRODITATUS 1117 4.50 126.61 5.30CHRYSICHTHYS AURATUS 1466. 5.90' 84.59- 3.54CLARO LES LATICEPS 226 0.91 22.10 0.92RETEROBRANCHUS BIDORSALIS 3 0.01 14.50 0.61CLARIUS ANGUELLARIS 729 2.93 157.79 6.60LATES NILOTICUS 963 3,88 210.3 t 8.80.

GYNNARCHUS-NILOTICUS .. 5 ... ...,.....0.02 1.20 0.05 .HE I hROTIS NILOTICUS 49 0.20 51.43 2.15SYNODONTIS NIGRITA 784 3.16 28.20 1.18

POLYMER-US ENDLICHER1 59 0 24 10 55 0.44 -AUCHENOGLANIS BISCUTATUS 302 : 122 24,12 1.01..

MORMYROPS DELICIOSUS 22 0.09 9.80 0.41HYPEROPISUS BEBE OCCEDENTALIS 163 0.66 27.20 1.14MARCUSENIUS ISIDOR : 113 0,45 10.95 0.46MALAPTERURUS.ELECTRICUS 33 0,1,3 .... - -..: 7.25 0,30SYNODONTIS FFLAMENTOSUS 54 0.22 2.72 0.11DISTICHODUS BREVEPPINIS 157 0.63 4.84 0.20PETROCEPHAUS BANE 66 027 326 0.14

24839 2389.30

35.30 1.48985 3.97 75.14 3.14

3 001 0.10 . 0051089 4-.38 23:88 0,10

67 0.27 4.54 0.1972 0.29 13.00 0.5411 0,04 765 0.32

608: 245 193,70 8,112209 8.89 133.44 5.58

8 0.03 10.25 0.43254. 1,02 4055: 1.70..

1458 5 86 15963:30 0.12 3.21 0.13

2743 11.04 124.42 5.21883 3 55 164 12. 6.87 .-

36 014 2,40 0:1063 0.25 3.10 0.13

69

ANNEX8COMMON NAMES OF FISH SPECIES CAUGHT BY FISHERFOLK IN KAINJI LAKE

Species Common name

ALESTES BAREMO SE Silver fishALESTES DENTEY Silver fish.ALESTES M4CROLEPIDOTUS Silver fishALESTES NURSE Silver fishAUCHENOGLANIS BISCUTA TUS CatfishAUCHENOGLANIS OCCIDENTALIS CatfishBAGRUS BA YAD Silver catfishBAGRUS DOCMAC Silver catfishCI-L4NA OBSURA Snake headCHRYSICHTHYS AURATUS Silver caffishCHRYSICHTHYS NIGRODIGITATUS Silver catfishCITHARINUS CITHARUS Moon fishCLAMS ANGUILLARIS MudfishCLAROTES LATICEPS CatfishDISTICHODUS BRELIPPINIS Grass eaterDISTICHODUS ROSTRATUS Grass eaterEUTROPIUS NILOTICUS Butter fishGYMNARCHUS NILOTICUS Trunk fishHETEROBRANCHUS BID ORSALIS CatashHETEROTIS NILOTICUS African bony tongueHYDROCYNUS BREWS Tiger fishHYDROCYNUS FORSKL1HLII Tiger fishHYPEROPISUS BEBE OCCIDEN'TALIS Trunk fishLABE° COUBIE African carpLABE° PSEUDOCOb'BIE African carpLABE° SENEGALENSIS African carpLATES NILOTICUS Nile perchMALIIPTERURUS ELECTRICUS Electric catfishMARCUSEIVIUS ISIDOR Trunk fish1IORMYROPS DELICIOSUS Tninic fishMORMYRUS RUME Trunk fishOREOCHROMIS NILOTICUS TilapiaPETROCEPFL1US BANE Trunk fishPOLYPTERUS ENDLICHERI Sail fish of BichirsSAROTHERODON GALILAEUS TilapiaSCHILBE MYSTUS Butter fishSIERRATHRISSA LEONENSIS Freshwater Sardine ( Clupeid)SYNODONTIS CLARIUS CatfishSYNODONTIS FILAMEIVTOSUS CatfishSYNODONTIS GAMBIENSIS CatfishS'YNODO.NTIS 1IEMBRANACEUS CatfishSIWODONTIS NIGRITA CatfishSYNODO1VTIS SCHALL CatfishTIL4PL1 ZILLI Tilapia

69

ANNEX8COMMON NAMES OF FISH SPECIES CAUGHT BY FISHERFOLK IN KAINJI LAKE

Species Common name

ALESTES BAREMOSE Silver fishALESTES DEN7'EX" Silver fish.ALESTES M4CROLEPIDOTUS Silver fishALESTES NURSE Silver fishAUCHENOGLANIS BISCUTA TUS CatfishAUCHENOGLANIS OCCIDENTALIS CatfishBAGRUS BA ITAD Silver catfishBAGRUS DOCMAC Silver catfishCIL4NA OBSUR4 Snake headCHRYSICHTHYS AURATUS Silver catfishCHRYSICHTHYS NIGRODIGITA TUS Silver catfishCITHARINUS CITHARUS Moon fishCLARLIS ANGUILLARIS MudfishCLAROTES LATICEPS CatfishDISTICHODUS BRELIPPINIS Grass eaterDISTICHODUS ROSTRATUS Grass eaterEUTROPIUS NILOTICUS Butter fishGYA/INARCHUS NILOTICUS Trunk fishHETEROBR4NCHUS BIDORSA LIS CatfishHETEROTIS NILOTICUS African bony tongueHYDROCYNUS BRELIS Tiger fishHYDROCYNUS FORSKL1HLII Tiger fishHYPEROPISUS BEBE OCCIDEN'TALIS Trunk fishLABEO COUBIE African carpLABE° PSEUDOCOb'BIE African carpLABE° SENEGALENSIS African carpL4 TES NILOTICUS Nile perchMALAPTERURUS ELECTRICUS Electric catfishJVL1RCUSENIUS ISIDOR Trunk fishMORMYROPS DELICIOSUS Trunk fishMORMYRUS RUME Trunk fishOREOCHROMIS NILOTICUS TilapiaPETROCEPHAUS BANE Trunk fishPOLYPTERUS ENDLICHERI Sail fish of BichirsSAROTHERODON GALILAEUS TilapiaSCHILBE MYSTUS Butter fishSIERRA THRISSA LEONENSIS Freshwater Sardine ( Clupeid)SYNODONTIS CLARIUS CatfishSYNODON'TIS FILAIIENTOSUS CatfishSYNODONTIS GAIIBIENSIS CatfishS'Y'A TODONTIS MEMBRANACEUS CatfishSIWODONTIS NIGRITA CatfishSYNODONTIS SCHALL CatfishTIL4PL1 ZILLI Tilapia

70

ANNEX9FISH SPOILAGE AT CHECKING AND LANDING BY SPECIES

Species name Wt/ fish Wt/ fish Spoilt Wt / fish spoilt % Wt ofCaught checking landing Spoilt fish

kg kg%/0 kg % caught 70'ALES'1ES BAREMOSE 75.1 4.2 5.6 1.2 1.6 1.2ALES'l ES DENTEX 0.1ALES'1ES MACROLEPIDOTUS 4.5 1 22.2 22.2ALES'1ES NURSE 23.9 1.8 7.5 0.3 1.3 8.8AUCHENOGLANIS BISCUTATUS 24.1 0.2 0.8 0.8AUCHENOGLANIS OCCIDENTALIS 65.3 2.3 3.5 2.8 4.3 7.8BAGRUS BAYAD 134.5 2.5 1.9 1 0.7 2.6BAGRUS DOCMAC 13 0.3 2.3 2.3CIIRYSICHTHYS AURATUS 84.6 14 16.5 7.2 8.5 25CIIRYSICHTHYS NIGRODITATUS 126.6 13.7 10.8 0.6 0.5 11.3CITHARINUS CITHARUS 193.7 8.1 4.2 3.6 1.9 6.1CLARIUS ANGUELLARIS 157.8 37.1 23.5 2.8 1.8 25.3CLARO'l ES LATICEPS 22.1 0.1 0.5 0.2 0.9 1.4DISTICHODUS BREVIPPINIS 4.8 1.1 22.9 22.9DISTICHODUS ROSTRATUS 133.4 19.6 14.7 5 3.7 18.4EUTROPLUS NILOTICUS 5.3 0.9 17 17GYMNARCHUS NILOTICUS 1.2HE1EROBRANCHUS BIDORSALIS 14.5HEIEROTIS NILOTICUS 51.4HYDROCYNUS BRE VIS 7.7HYDROCYNUS FORSKAHLII 13.0 2.3 17.7 0.7 5.4 23.1HYPEROPISUS BEBE OCCIDENTALIS 27.2 1.1 4.1 0.2 0.7 4.8LABE° COUBIE 40.6 2.1 5.2 2.3 5.7 10.9LABE° PSEUDOCOUBIE 10.3LABEO SENEGALENSIS 159.6 27.9 17.5 18.1 11.3 29.4LA'l ES NILOTICUS 210.3 13.1 6.2 9 4.3 10.5MALAPTERURUS ELECTRICUS 7.3 0.2 2.7 2.7MARCUSENIUS ISIDOR 11.0 0.2 1.8 1.8MORM'YROPS DELICIOSUS 9.8 1.4 14.3 14.3MORMYRUS RUME 13.7 0.4 2.9 2.9

OREOCIIR.OMIS NILOTICUS 357.3 35.2 9.8 13.4 3.8 13.6PETROCEPHAUS BANE 3.3 0.5 15.2 15.2POLYPTERUS ENDLICHERI 10.6 0.9 8.5 0.5 4.7 13.2SAROTTHERODON GALILAEUS 3.1S CHILBE MYSTUS 4.7 0.3 6.4 6.4SIERRATHRISSA LEONENSIS 35.3SYNODONTIS CLARIUS 3.2SYNODONTIS FILAMENTOSUS 2.7 0.1 3.7 3.7SYNODONTIS GAMBIENSIS 2.4SYNODONTIS MEMBRANACEUS 164.1 11 6.7 0.8 0.5 7.2SYNODONTIS NIGRITA 28.2 0.8 2.8 2.8SYNODONTIS SCHALL 124.4 0.9 0.7 1.6 1.3 2TILAPIA ZILLI 3.7

70

ANNEX9FISH SPOILAGE AT CHECKING AND LANDING BY SPECIES

Species name Wt/ fishCaught

kg

Wt/ fish Spoiltcheckingkg%/0

Wt / fish spoiltlanding

kg %

% Wt ofSpoilt fishcaught :%

ALESTES BAREMOSE 75.1 4.2 5.6 1.2 1.6 1.2ALESTES DENTEX 0.1ALESTES MACROLEPLDOTUS 4.5 1 22.2 22.2ALESIES NURSE 23.9 1.8 7.5 0.3 1.3 8.8AUCHENOGLANIS BISCUTATUS 24.1 0.2 0.8 0.8AUCHENOGLANIS OCCIDENTALIS 65.3 2.3 3.5 2.8 4.3 7.8BAGRUS BAYAD 134.5 2.5 1.9 1 0.7 2.6BAGRUS DOCMAC 13 0.3 2.3 2.3CHRYSICHTHYS AURATUS 84.6 14 16.5 7.2 8.5 25CHRYSICHTHYS NIGRODITATUS 126.6 13.7 10.8 0.6 0.5 11.3CITHARINUS CITHARUS 193.7 8.1 4.2 3.6 1.9 6.1CLARIUS ANGUILLARIS 157.8 37.1 23.5 2.8 1.8 25.3CLAROTES LATICEPS 22.1 0.1 0.5 0.2 0.9 1.4DISTICHODUS BREVIPPINIS 4.8 1.1 22.9 22.9DISTICHODUS ROSTRATUS 133.4 19.6 14.7 5 3.7 18.4EUTROPLUS NILOTICUS 5.3 0.9 17 17GYMNARCHUS NILOTICUS 1.2HEIEROBRANCHUS BLDORSALIS 14.5HE I EROTIS NILOTICUS 51.4HYDROCYNUS BREVIS 7.7HYDROCYNUS FORSKAHLII 13.0 2.3 17.7 0.7 5.4 23.1HYPEROPISUS BEBE OCCIDENTALIS 27.2 1.1 4.1 0.2 0.7 4.8LABEO COUBIE 40.6 2.1 5.2 2.3 5.7 10.9LABE° PSEUDOCOUBIE 10.3LABEO SENEGALENSIS 159.6 27.9 17.5 18.1 11.3 29.4LA IES NILOTICUS 210.3 13.1 6.2 9 4.3 10.5MALAPTERURUS ELECTRICUS 7.3 0.2 2.7 2.7MARCUSENIUS IS1DOR 11.0 0.2 1.8 1.8MORMYROPS DELICIOSUS 9.8 1.4 14.3 14.3MORMYRUS RUME 13.7 0.4 2.9 2.9OREOCHROMIS NLLOTICUS 357.3 35.2 9.8 13.4 3.8 13.6PETROCEPHAUS BANE 3.3 0.5 15.2 15.2POLYPTERUS ENDLICHERI 10.6 0.9 8.5 0.5 4.7 13.2SAROTHERODON GALILAEUS 3.1SCHELBE MYSTUS 4.7 0.3 6.4 6.4SlERRATHRISSA LEONENSIS 35.3SYNODONTIS CLARIUS 3.2SYNODONTIS FILAMENTOSUS 2.7 0.1 3.7 3.7SYNODONTIS GAMBIENSIS 2.4SYNODONTIS MEMBRANACEUS 164.1 11 6.7 0.8 0.5 7.2SYNODONTIS NIGRITA 28.2 0.8 2.8 2.8SYNODONTIS SCHALL 124.4 0.9 0.7 1.6 1.3 2TILAPIA ZILLI 3.7

71

ANNEX 10

DISTRIBUTION OF TRADITIONAL SMOKING KILNS "BANDA" IN SOME FISHING VILLAGES AROUND KAINJI LAKE BASIN

Shagunu

4

Malale

6

30

138

5 --

- -

- -

39

144

Foge

Island

-4

--

17

21

Kokoli

28

5-

--

33

Tungan Tsamiya

16

2-

--

18

Angwan Salikawa

5190

--

-195

Amboshidi

6120

--

-126

Gungun Sarki

-22

--

-22

Tungan Leda

-35

--

-35

Yauri

--

43

58

-101

Monai

20

30

--

--

50

Wawu

15

45

--

--

60

Warra

83

195

--

--

188

Total=

183

762

943

58

17

1032

Percentage =

17.73

73.83

0.87

4.16

5.62

1.65

Villages

Traditional Smoking

Kilns "Banda"

Circular

Rectangular

Rectangular

Drum

Type

Pit

Total

mud

mud

Iron Roofing

Circular

Rectangular

Type

Sheet

71

ANNEX 10

DISTRIBUTION OF TRADITIONAL SMOKING KILNS "BANDA" IN SOME FISHING VILLAGES AROUND KAINJI LAKE BASIN

Shagunu

Malale

4 6

30

138

5

-

- -

- -

39

144

Foge Island

--

4-

-17

21

Kokoli

28

5-

--

33

Tungan Tsamiya

16

2_

--

18

Angwan Salikawa

5190

_-

-195

Amboshidi

6120

--

-126

Gungun Sarki

-22

--

-22

Tungan Leda

-35

--

35

Yauri

-43

58

-101

Monai

20

30

_-

--

50

Wawu

15

45

--

-60

Warra

83

195

--

--

188

Total=

183

762

943

58

17

1032

Percentage =

17.73

73.83

0.87

4.16

5.62

1.65

Villages

Traditional Smoking

Kilns "Banda"

Circular

Rectangular

Rectangular

Drum

Type

Pit

Total

mud

mud

Iron Roofing

Circular

Rectangular

Type

Sheet

72

ANNEX 11PLACES OF DISPOSAL OF FISH FROM KAINJI LAKE BASIN

Place Number

Abuja 16Bida 2

Bussa 15Dogongari 1

Gombe 1

Gongola 1

Ibadan 6

Igboho 1

Ilorin 12Kabba 1

Kaiama 5

Kaduna 5

Kont agora 5

Lagos 17Malale 5

Minna 1

Mokwa 1

Nasco 3

Offa 1

Onitsha 11Salka 1

Shaki 2

Suleja 10Wara 2

72

ANNEX 11PLACES OF DISPOSAL OF FISH FROM KAINJI LAKE BASIN

Place Number

Abuja 16Bida 2

Bussa 15Dogongari 1

Gombe 1Gongola 1

Ibadan 6

Igboho 1

Ilorin 12Kabba 1

Kaiama 5

Kaduna 5

Kontagora 5

Lagos 17Malale 5

Minna 1

Mokwa 1

Nasco 3

Offa 1

Onitsha 11Salka 1

Shaki 2

Suleja 10Wara 2

BIBLIOGRAPHY

Awoyemi, M.D. (1988). Insect infestation of dried fish in theKainji Lake area. NIFFR Annual Report 1988. 183-190

Anthonio Q.B.O. (1995). Fish Marketing Survey in the Kainji LakeBasin. Report prepared for the Nigerian-German (GTZ) KainjiLake Fisheries Promotion Project. 119pp.

Araf, M.A; Timbely and J. Degot 1964. Fish and fish processing inthe Republic of Mali on the destruction of dried fish by thedermestic insects. Alex. J. AcTric. Res. 12 (2) 95-108.

Azeza, N.I. (1980). Traditional processing of fish in Lake Chadareas and the potential for improvement. Paper presented at aSeminar on Inspection and Quality Control, Lagos. 8.p,

Bostock, T.W. (1987). Marine Fisheries of Gujarat. Post-harvestlosses and possibilities for development, Report of theTropical Development and Research Institute L 75, Vt 32pp.

Clifford, M.A., Tang S.and Eyo A.A. (1980). Smoking of foods.Process Biochemistry June/July p.8.

Clucas, L.J. (Compiler) (1982) Fish handling, preservation andprocessing in the tropics. Part I, Report of the TropicalProducts Institute 9145 Vii.144.

Dada B.F. and D.A.S. Gnanados (1983). Nigerian FisheriesDevelopment: Challenges and opportunities of the 1980's. Inthe proceedings of the 3rd annual Conference of the FisheriesSociety of Nigeria (FISON) Maiduguri 22nd - 25th February,1983 pp. 14-24.

Dampha, N.J. (1993). The smoking of Luciolates stoppersi (Migebuka)in the Kigoma Region of Lake Tanganyika, Tanzania. FAOFisheries Report No. 467 pp 104 - 107.

Eyo, A.A. (1977a) An appraisal of the traditional fish handlingand processing in Kainji Lake area. KLRI. Newsletter 3 (2)

1977.

Eyo, A.A. (1977b) Effect of different handling methods on thekeeping quality of some commercial important fish species onLake Kainji Nigeria pp 46 KLRI Prog. Report April - March 1977

Eyo, A.A. (1981). The construction and operation of a newmechanical gas smoking kiln (Kainji Gas Kiln) K.L.R.I.Technical Report series No 7. 13p.

73

BIBLIOGRAPHY

Awoyemi, M.D. (1988). Insect infestation of dried fish in theKainji Lake area. NIFFR Annual Report 1988. 183-190

Anthonio Q.B.O. (1995). Fish Marketing Survey in the Kainji LakeBasin. Report prepared for the Nigerian-German (GTZ) KainjiLake Fisheries Promotion Project. 119pp.

Araf, M.A; Timbely and J. Degot 1964. Fish and fish processing inthe Republic of Mali on the destruction of dried fish by thedermestic insects. Alex. J. Agric. Res. 12 (2) 95-108.

Azeza, N.I. (1980). Traditional processing of fish in Lake Chadareas and the potential for improvement. Paper presented at aSeminar on Inspection and Quality Control, Lagos. 8.p,.

Bostock, T.W. (1987). Marine Fisheries of Gujarat. Post-harvestlosses and possibilities for development, Report of theTropical Development and Research Institute L 75, Vt 32pp.

Clifford, M.A., Tang S.and Eyo A.A. (1980). Smoking of foods.Process Biochemistry June/July p.8.

Clucas, L.J. (Compiler) (1982) Fish handling, preservation andprocessing in the tropics. Part I, Report of the TropicalProducts Institute 9145 Vii.144.

Dada B.F. and D.A.S. Gnanados (1983). Nigerian FisheriesDevelopment: Challenges and opportunities of the 1980's. Inthe proceedings of the 3rd annual Conference of the FisheriesSociety of Nigeria (FISON) Maiduguri 22nd - 25th February,1983 pp. 14-24.

Dampha, N.J. (1993). The smoking of Luciolates stoppersi (Migebuka)in the Kigoma Region of Lake Tanganyika, Tanzania. FAOFisheries Report No. 467 pp 104 - 107.

Eyo, A.A. (1977a) An appraisal of the traditional fish handlingand processing in Kainji Lake area. KLRI. Newsletter 3 (2)

1977.

Eyo, A.A. (1977b) Effect of different handling methods on thekeeping quality of some commercial important fish species onLake Kainji Nigeria pp 46 KLRI Prog. Report April - March 1977

Eyo, A.A. (1981). The construction and operation of a newmechanical gas smoking kiln (Kainji Gas Kiln) K.L.R.I.Technical Report series No 7. 13p.

73

74

Eyo, A.A. (1983) The significance of fish handling, preservationand processing in the development of Inland Fishery withspecial reference to Kainji Lake. Proc. 3rd Ann. Conf. Fish.Soc. Nig. 115-122.

Eyo, A.A. (1985) Evaluation of the Colour and Flavour of tilapiasmoked with different wood types. Trop. Sci. 25. 265-270

Eyo, A.A. (1989). Artisanal fish handling, preservation andprocessing in Nigeria-problems and prospects. In proceedingsof the Conference of Two Decades of Research on Lake Kainji,Nigeria. eds. Ayeni J.S.0 and Olatunde A.A. pp. 167-178.

Eyo, A.A. (1992a) Utilization of freshwater fish species inNigeria. In proceedings of the 10th Annual Conference of theFisheries Society of Nigeria (FISON) Eds A.A. Eyo andA.M.Balogun. pp. 32-37.

Eyo, A.A. (1992b). Studies on the Biochemical composition andnutritive value of Clupeids (Pellonula afzeliusi andSierrathrissa leoneneis) Nigeria Food Journal Vol. 10.111-115.

Eyo A.A. (1993a). Comparative study of the quality of smoked fishfrom four different smoking kilns. FAO Fisheries Report No.467 pp. 93-95.

Eyo, A.A. (1993b) Shelf-life of Moonfish (Citharinus citharus) andTrunk fish (Mormyrus rume) during storage at ambienttemperature and on ice NIFFR Annual Report 1993 pp. 62-75.

Eyo, A.A. and Awoyemi, M.D. (1990) Survey of fish handling,preservation and marketing in Asa Dam Reservoir at Ilorin,Kwara State. 12pp. (unpublished report deposited at NIFFRLibrary).

FAO, (1981) The prevention of losses in cured fish. FAO Fish Tech.Papers. No. 219. 87pp. FAO. Rome.

Haines, C.P. (1984) Insects and arachinols from stored products: areport on specimens received by the Tropical stored productscentred.1973-77 Rep. Trop. Prod. Inst. (L54): 73p.

Huss, H.M. (1988) Fresh fish quality and quality changes.FAO/DANIDA Training programme on fish Technology and Qualitycontrol. FAO Fisheries Series No 29, 132pp.

James, D.G. (1977) Post harvest losses of marine foods -products:Paper presented to the Institute of Food Technology 37thAnnual meting. Philadephia. Pennsylvania. 5-8 June 1977 15pp

74

Eyo, A.A. (1983) The significance of fish handling, preservationand processing in the development of Inland Fishery withspecial reference to Kainji Lake. Proc. 3rd Ann. Conf. Fish.Soc. Niq. 115-122.

Eyo, A.A. (1985) Evaluation of the Colour and Flavour of tilapiasmoked with different wood types. Trop. Sci. 25. 265-270

Eyo, A.A. (1989). Artisanal fish handling, preservation andprocessing in Nigeria-problems and prospects. In proceedingsof the Conference of Two Decades of Research on Lake Kainji,Nigeria. eds. Ayeni J.S.0 and Olatunde A.A. pp. 167-178.

Eyo, A.A. (1992a) Utilization of freshwater fish species inNigeria. In proceedings of the 10th Annual Conference of theFisheries Society of Nigeria (FISON) Eds A.A. Eyo andA.M.Balogun. pp. 32-37.

Eyo, A.A. (1992b). Studies on the Biochemical composition andnutritive value of Clupeids (Pellonula afzeliusi andSierrathrissaleoneneis) Nigeria Food Journal Vol. 10.111-115.

Eyo A.A. (1993a). Comparative study of the quality of smoked fishfrom four different smoking kilns. FAO Fisheries Report No.467 pp. 93-95.

Eyo, A.A. (1993b) Shelf-life of Moonfish (Citharinus citharus) andTrunk fish (Mormyrus rume) during storage at ambienttemperature and on ice NIFFR Annual Report 1993 pp. 62-75.

Eyo, A.A. and Awoyemi, M.D. (1990) Survey of fish handling,preservation and marketing in Asa Dam Reservoir at Ilorin,Kwara State. 12pp. (unpublished report deposited at NIFFRLibrary).

FAO, (1981) The prevention of losses in cured fish. FAO Fish Tech.Papers. No. 219. 87pp. FAO. Rome.

Haines, C.P. (1984) Insects and arachinols from stored products: areport on specimens received by the Tropical stored productscentred.1973-77 Rep. Trop. Prod. Inst. (L54): 73p.

Huss, H.M. (1988) Fresh fish quality and quality changes.FAO/DANIDA Training programme on fish Technology and Qualitycontrol. FAO Fisheries Series No 29, 132pp.

James, D.G. (1977) Post harvest losses of marine foods -products:Paper presented to the Institute of Food Technology 37thAnnual meting. Philadephia. Pennsylvania. 5-8 June 1977 15pp

75

Ladipo 0.01 Y.L. Fabiyi and G.T. Fatunla (1981). Marketing anddistribution of fish in Nigeria. A technical report submittedto the Federal Department of Fisheries Lagos. 84pp.

Mayboom B. (1975). Fish handling and processing in the Kainji LakeBasin and suggestion for improvements and future research. FAORome FIDP/NIR/66/524/12. 21pn.

Osuji, F.N.C. (1974) Beetle infestation in dried fish purchasedfrom a Nigerian market with special reference to Dermestesmaculatus and Necrobia rufipes. Niger. J. Entomol. 1: 69-70

Poulter, R.G., Ames, G.R., and Evans, N.J. (1986) Post harvestlosses in traditionally processed fish nroducts in lessdeveloned countries. Proceedings of an international Workshop

on Post harvest Fishery Losses held at University ofRhode Island, U.S.A. ed. M.T. Morrissey. p. 133-145.

Proctor, D.L. (1977) The control of insect infestation of fishduring processing and storage in the tropics. Proc. Conf. onHandling and marketing of Fish. Tp1. 307-311.

Regenstein J.M and C.E. Regenstein (1991). Introduction to fishtechnology. An Osprey book published by Van Nostrand, NewYork, 269pp.

Rollings, M.J. and Hayward, L.A.W. (1963) Aspects of the dried fishtrade in Nigeria with particular reference to :Lake Chad. Tron.Stored Prod. Inf. S: 162-167.

Stroud G.D. (1969). Rigor in fish. The effect on quality. Torry- Advisory Note No. 36 HMSO Press Edinburgh llpp.

Tobqr T.G. (1984). The fisheries Industry in Nigeria Status of Fishpreservation methods and future growth pre-requisites to copewith anticipated production. In: Proceedings of the symposiumon fisheries development. Sponsored by Almarine 31st August1984 pp. 85 - 105.

Tobor, J.G. (1993). Finfish and shellfish of conservation interestin Nigeria. Proceedings of the National Conference onConservation of Aquatic resources edited by Eborge et alNational Resources Conservation Council (NARESCON) 1993.pp.104-129

Toth, L. (1982) Chemie der Raeucherung, Verlag Chemie, Weinheim,Germany.

Wheaton, F.W. and T.B. Lawson (1985) Processing aquatic foodproducts. A Wiley - interscience publication. New York 328pp.

75

Ladipo 0.01 Y.L. Fabiyi and G.T. Fatunla (1981). Marketing anddistribution of fish in Nigeria. A technical report submittedto the Federal Department of Fisheries Lagos. 84pp.

Mayboom B. (1975). Fish handling and processing in the Kainji LakeBasin and suggestion for improvements and future research. FAORome FIDP/NIR/66/524/12. 21pp.

Osuji, F.N.C. (1974) Beetle infestation in dried fish purchasedfrom a Nigerian market with special reference to Dermestesmaculatus and Necrobia rufipes. Niger. J. Entomol. 1: 69-70

Poulter, R.G., Ames, G.R., and Evans, N.J. (1986) Post harvestlosses in traditionally processed fish products in lessdeveloped countries. Proceedings of an international Workshop

on Post harvest Fishery Losses held at University ofRhode Island, U.S.A. ed. M.T. Morrissey. p. 133-145.

Proctor, D.L. (1977) The control of insect infestation of fishduring processing and storage in the tropics. Proc. Conf. onHandling and marketing of Fish. Tp1. 307-311.

Regenstein J.M and C.E. Regenstein (1991). Introduction to fishtechnology. An Osprey book published by Van Nostrand, NewYork, 269pp.

Rollings, M.J. and Hayward, L.A.W. (1963) Aspects of the dried fishtrade in Nigeria with particular reference to Lake Chad. Trop.Stored Prod. Inf. S: 162-167.

Strcud G.D. (1969). Rigor in fish. The effect on quality. Torry- Advisory Note No. 36 HMSO Press Edinburgh llpp.

Tobqr T.G. (1984). The fisheries Industry in Nigeria Status of Fishpreservation methods and future growth pre-requisites to copewith anticipated production. In: Proceedings of the symposiumon fisheries development. Sponsored by Almarine 31st August1984 pp. 85 - 105.

Tobor, J.G. (1993). Finfish and shellfish of conservation interestin Nigeria. Proceedings of the National Conference onConservation of Aquatic resources edited by Eborge et alNational Resources Conservation Council (NARESCON) 1993.pp. 104-129

Tcth, L. (1982) Chemie der Raeucherung, Verlag Chemie, Weinheim,Germany.

Wheaton, F.W. and T.B. Lawson (1985) Processing aquatic foodproducts. A Wiley - interscience publication. New York 328pp.