INTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTION

INTRODUCTION

Fishes form an important nutritious food item of man. The

importance of fish as food has been recognised by man from antiquity.

FAO (Food and Agricultural Organizsation) has recognized the

importance of fish as a food source particularly for its role in protein

supply. In its first report on Fisheries, FAO stated that “… fish should be

regarded as one of the most important sources of food in any program

for raising the nutritional level of people throughout the world”. It

provides high quality protein and a wide variety of vitamins and

minerals. On average, fish provides about 20–30 kilocalories per person

per day. Experts agree that even in small quantities fish can have a

significant positive impact of improving the quality of dietary proteins.

Approximately one billion people worldwide rely on fish as the most

significant source of animal protein in their diets. More than 75% of the

world’s fish production is consumed by humans and remaining is fed to

animals, particularly in the form of fishmeal. Asia is the first largest fish

consuming continent and Europe stands second in fish consumption

whereas the lowest level of consumption occurs in Africa and the near

east. The demand for fish food in recent years is in the range of 110 to

120 million tonnes/year. Fish consumption rose to a record 17.2 kg per

person per year and would rise further as more people recognised the

benefits of seafood, the UN's Food and Agriculture Organization (FAO,

2011) said in a report.

Fishes also provide many other important by-products like fish oil,

fish meal, fish flour, fish protein, fish glue, fish skins. Fish liver oil is an

important natural source of Vitamin A. It also contains small quantities

of Vitamin D, C and E. Fishes like mackerel, salmon, herrings, sardines,

cods, halibuts, tunas, sharks and rays are the best oil yielders. Fish oil is

widely used for the manufacture of edible oil, margarine, lard-

substitutes, soap, paints and varnishes. Omega -3 is the name of a type of

fat that is found in oil-rich fish. Fish protein concentrate (FPC) is stable

fish preparation, intended for human consumption.

India is the third largest producer of fish in the world and second

in inland fish production. Fisheries are important for the Indian economy

as it provides employment opportunities and is a source of a nutritional

food and foreign exchange earnings. Fish production in the country has

been growing continuously with improvement in productivity and

utilization of untapped resources. The total fish production is 6.4 million

metric tones/year of which 3.4 million metric tonnes is inland and the

remaining 3.0 mmt is from marine environment.

Andhra Pradesh has been contributing significantly to the fish

basket of the country in the recent years through an effective strategy in

both coastal and freshwater aquaculture and marketing. The inland fish

production is 6.8 lakh tonnes. Further, by virtue of its 974 km long

coastline, the state produces 2.97 lakh tonnes of marine fish annually. It

stands second in fresh water fish production and fifth in marine fish

production.The advent of mechanisation of fishing craft and introduction

of mechanised fishing vessels has brought significant changes in the

marine fishing industry of Andhra Pradesh. As a result of this, the

fisheries harbour at Visakhapatnam has become one of the key harbours

for mechanised trawl fishing and Visakhapatnam itself has emerged as

one of the most important centres for exporting marine products to

foreign countries. Visakhapatnam coast has a special place in the marine

fisheries map of India being the nucleus of deep sea trawling activities

and various other mechanised and non-mechanised gear operations. A

number of fish landing centres dot along the 130 km coastline with about

185,948 tonnes of fish harvested annually.

Fish form an important dietary component of man. Since, it is

important the fish that are consumed should be healthy and free of

infection ensuring food safety. Infections which are caused by viruses,

bacteria and parasites among fishes in natural and manmade culture

systems are harmful for fish health and growth and sometimes are very

fatal, causing high mortalities. The major parasitic groups found in

marine and freshwater fishes are trematodes, cestodes, acanthocephalans

and nematodes. Parasite infested fish have no or low market value

resulting in loss to fishery industry. Hence it is relevant to identify such

infectious agents and suggest measures for prevention and elimination of

such infections.

It is well documented that many groups of helminths, affecting the

host in different ways by causing mechanical injuries such as irritation,

injury or atrophy of tissue and occlusion of the alimentary canal, blood

vessels or other ducts; introducing toxic metabolic byproducts able to

produce changes in the blood, enzyme, vitamin or hormone activity of

the host. The host reaction may be tissue proliferation, degeneration and

inflammation and probably in the development of immunity. On the

other hand, parasitic infestations affect the metabolic rate of the fish and

result in stunted growth of the fish. A heavy worm infection reduces the

host’s reproductive potential as in the case of nematode infection with

Philometra or delay the sexual maturity in the fish, both the factors

limiting the size of the host population.

Parasites show deleterious effects on the biology of the host in many

ways. Pathogenicity of fish parasites is now increasingly attracting the

attention of parasitologists, with a considerable significance to the effects

of nematodes on their fish hosts compared to other parasitic helminths. The

importance of fish parasites as a factor contributing to fish mortality should

not be underestimated, especially in fish farming and culture, where

sometimes the whole population of the pond is killed, resulting in the loss

of potential food and incurring financial loss to the farmer.

The highly specific diets among fishes may result in very low

infection with parasites. A more generalized diet on the other hand,

exposes hosts to greater diversity of parasites. Fish serve as the

intermediate or reservoir hosts for larval stages of some nematode

species and as definitive hosts in which sexual maturity is attained for

others. The larval forms of nematodes generally occur in abundance,

which is probably attributable to a life span covering several years. Such

consequent nematode accumulation increases with age of the fish. Many

adult nematode associations with fish, especially those living in the

digestive tract have shorter life span. The larvae live in the skin or in the

internal organs where they encyst. The cysts, when present, cause

inflammation of the internal organs. The cyst produces larva and

develops into the adult worm when the fish is eaten by the definitive

host. The nematodes one usually found in the gut, body cavity, muscles,

blood – vessels, swim bladder, gonads and other organs of the fish. Such

nematodes of fishes probably have a two-host or three-host life cycles.

Certain nematodes parasitize both external and internal organs of fish.

Nematode parasites of fish are also important from human health

point of view. The larvae of Gnathostoma spinigerum, usually encyst in the

muscle of fish, can be ingested by humans with under-cooked fish flesh

which then develop to morphologically mature but sexually immature

worms thus, showing zoonotic potential. These worms become erratic and

find their way into the skin, mucous membranes on the visceral lining, the

eye and the brain.The third stage larvae of ascaridoid nematodes from

marine fish can infect man if ingested raw or lightly salted.

It is important to know that in which species of the fish and under

what circumstances these parasites are able to live and develop. It is

equally important to know the seasonal occurrence of fish parasites. This

knowledge is very important from the practical point of view.

The numerous species of nematodes reported from fishes all over

the world, host specificity and evolution of nematode parasites, which

could form another important piece of research work. The nematode

fauna of fishes in South Asia is now fairly well known. The widely

scattered literature discussing the morphology and taxonomy of

nematode parasites from various regions generally consists of the

descriptions of new taxa, with little or no biological information about

the parasites or host-parasite relationship, although a beginning has

already been made, the parasitic fauna of marine and freshwater needs to

be explored.

Ichthyopathological effects of nematode infections of common fish,

their taxonomical aspects and some of the important larval stages of

nematodes in their definitive hosts are undertaken.

The systematics of nematode parasites need to be repeated atleast

once in 10 years because of the fast changing aquatic environment due to

the interference of human activity and to help in completing the records

pertaining to ecology, biodiversity in relation to geography and the host

parasite relations. In view of the growing importance of fisheries in India

and abroad an attempt has been made to enhance the knowledge of

nematode parasites of fishes and intensity of their infection.

Some of the important early investigations on nematode parasites of

fish include those of Mueller (1777), Rudolphi (1810, 1819), Fourment

(1883), Linton (1891, 1901), Johnstone (1906), Railliet and Henry (1912)

and Travassos (1917). Ward and Magath (1917) gave an account on

nematodes in freshwater fishes. Barreto and De (1918) published a compiled

account of nematodes. Baylis and Lane (1920) published a detailed review

of nematodes of Gnathostomidae. Barreto and De (1922) revised the

nematodes of Cucullanidae. Baylis (1922) reported nematodes from fishes of

the river Nile. Baylis and Daubney (1922, 1923) reported a detailed account

of parasitic nematodes in the collection of the Zoological survey of India.

Baylis (1923a) collected parasitic nematodes mainly from Egypt.

Baylis (1923b) worked on some nematodes of the genus Cucullanus from

the fishes of the river Nile. Baylis and Daubney (1926) gave a detailed

systematic account of nematodes. Gendre (1927) studied in brief on parasitic

nematodes. Thwaite (1927) published on a collection of nematodes from

Ceylon. Fujita (1928) studied the parasitic nematodes from fishes of Lake

Biwa, Japan. Tornquist (1931) published the anatomical and histological

details of parasitic nematodes of Cucullanidae and Camallanidae. Das and

Rahimullah (1933) published a note on nematodes of India. Hsu (1933)

reported some species of parasitic nematodes from fishes of China. Smedley

(1933 a, b) worked on nematode parasites from Canadian marine and

freshwater fishes. Chandler (1935) described some parasitic nematodes of

Galveston Bay of United states of America. Dollfus (1935) described three

species of parasitic nematodes. Kulkarni (1935) described a nematode

species of Procamallanus from India.

Yamaguti (1935) studied in detail on the nematodes of fishes from

Japan. A detailed description on nematode fauna of British India including

Ceylon and Burma was published by Baylis (1936 & 1939). Johnston and

Mawson (1940) described some nematodes parasitic in Australian

freshwater fish. Karve (1941) reported some parasitic nematodes of fishes.

Yamaguti (1941) published a systematic and histological account of

nematodes in the fishes of Japan. Johnston and Mawson (1942) worked on

some new and known Australian parasitic nematodes. Chandler (1943)

described a species of nematode Contracaecum habena. Johnston and

Mawson (1943) described some nematodes from Australian elasmobranchs.

Baylis (1944) compiled the works on parasitic nematodes. Johnston and

Mawson (1945) worked on parasitic nematodes from Australian fishes.

Skrjabin (1946) revised the taxonomy of the nematodes parasitising in

fishes.

Other contributions were of karve and Naik (1951) on some parasitic

nematodes of fish. Karve (1952) described some of the parasitic nematodes

of fishes of India. Olsen (1952) published on some parasitic nematodes of

marine fishes. Khera (1953) described Pseudoproleptus vestibules n.g., n.sp

from the fish, Mastacembelus armatus. Khera (1954) worked on nematode

parasites of some Indian vertebrates. Saidov (1954) revised the family

Rhabdochonidae and the subfamily Cyclozoninae. Khera (1955) studied

some nematode species of Procamallanus from India. Ali (1956) made

studies on the nematode parasites of fishes and birds in Hyderabad state.

Hartwich (1957) published a detailed systematic account of Superfamily

Ascaridoidea of nematodes. Gupta (1959) studied the nematode parasites of

vertebrates of East Pakistan. Ali (1960) collected two new species of

nematode Procamallanus from India, and published a key upto the species

level. Chakravarthy and Majumdar (1960) described two new species of

nematodes Procamallanus from India, and gave a key to identify upto the

species level. Berland (1961) worked on nematodes from some Norwegion

marine fish. Skrjabin, et al., (1961) published a volume where he compiled a

detail account on morphological, anatomical and systematics of nematodes.

Yamaguti (1961) compiled the works of others and brought out information

from all over the world in his compendium “Systema Helminthum”.

Chakravarthy and Majumdar (1962) collected new nematode parasites from

bird and fish. Fernando and Furtado (1963) studied nematodes in fresh water

fishes in Ceylon. Hopper (1963) reported marine nematodes from the

Coastline of the Gulf of Mexico.

Kreis (1963) made a brief report on marine nematodes from Iceland.

Skrjabin and Sobolev (1964) worked on Spirurid nematodes. Agrawal (1965

a, b) described some new nematode parasites from fresh water fish of

Lucknow, India. Furtado (1965) reported nematode Rhabdochona pengensis

n.sp from a Malayan Cyprinid fish and Lee (1965) studied the physiology of

nematodes.

Rasheed (1965 a, b, c) published on some of the new species of

nematodes from marine fishes of Karachi, Pakistan. Crofton (1966)

published on general account of nematode parasites. Johnson (1966) worked

on the systematic of nematodes. Molnar (1966) described some little known

and new nematode species of the genera Philometra and Skrjabillanus from

fishes in Hungary. Rasheed (1966) described some interesting nematode

parasites of fish from Pakistan. Sahay and Sinha (1966) reported nematode

Zeylanema mastacembeli n.sp from Mastacembelus armatus. Sood (1966)

collected two new nematode parasites from freshwater fishes of Lucknow.

Sahay (1966 a, b, c) described three species of nematodes Procamallanus,

Rhabdochona bosei n.sp and Haemonchus contortus.

Agrawal (1967) published some new Camallanoidea (spirurida)

nematodes from fishes, amphibians and reptiles. James and Srivastava

(1967) described some nematode parasites from five bearded rocking fish

Onos mustelus from Mumbles head, Swansea. Sahay and Narayan (1967)

published on the nematode family Camallanidae with its classification.

Margolis (1968) published some nematode parasites from Salmonid fishes.

Further Sahay (1968) and Sood (1968 a, b) reported some nematode

parasites from freshwater fishes of India. Kalyankar (1969) worked on some

nematode parasites, Mehdiascaris n.g and two new species of ascarids from

a marine fish Muraenesox talabanoides. Further work on nematodes was

done by Misra (1969) who worked on the fauna of India and adjacent

countries. Rai (1969) worked on some of the hitherto known and unknown

nematodes parasitic in some of the freshwater siluroid fishes.

Sahay, et al., (1969) also worked on Rhabdochonid nematode

parasites from fishes of India. Troncy (1969) described some nematode

parasites. Chitwood (1970) also worked on fish nematodes. Freitas, et al.,

(1970) studied a new Camallanid nematode parasite of fish in Peru.

Kalyankar (1970) reported a new nematode, Alibagascaris pseudosciaenae

gen et n.sp from marine fishes of Alibag and Bombay, India. Sood and

Agarwal (1970) discussed on two nematode parasites of fishes from

Lucknow. Bilquees, et al., (1971) studied the marine fish nematodes of West

Pakistan.

Kalyankar (1971 a,b,c,d,e,f,g) described six new species of

nematodes, Thynnascaris carangis n.sp., Neospinitectus ophiocephali n.g,

n.sp and new species of Philometra and Pseudocucullanus tachysuri n.g.

n.sp Neocucullanellus yamaguti n.sp and Aliascaris indica collected from

fishes Caranx malabaricus, Ophiocephalus punctatus and Trygon sephen.

Further investigation was done by Khan and Begum (1971) on nematode

parasites of fishes from West Pakistan. Majumdar and De (1971) described a

nematode Rhabdochona barusi n.sp from the fish Barilius sp with the key to

the Indian species of this genus. Mohan (1971) discussed on the infestation

of the gonadial nematode parasite Philometra rajani from the sciaenid fish

Pennahia aneus. Moravec (1971) worked on nematodes of fishes in

Czechoslovakia. Rasheed Ilyas (1971) studied nematode parasites of fishes,

amphibia, birds and reptiles of Maharashtra State of India. Soota and

Chaturvedi (1971 a, b, c) reported some nematodes from the unnamed

collection of the Zoological Survey of India.

Further investigations was done by Bilquees and Khanum (1972) and

Chitwood and Lichenfels (1972) on the marine fish nematodes. Kalyankar

(1972 a, b, c) reported some new nematodes from India. Moravec (1972)

discussed the general characterization of the nematode genus Rhabdochona

with a revision of the South American species. Sood (1972 a, b, c) worked

on some nematode parasites from freshwater fishes of India. Soota and

Chaturvedi (1972) described the nematode fauna of Goa, India. Verma

(1972) worked on nematode parasites of freshwater fishes and described two

new species of the genus Rhabdochona from Lucknow. Bashirullah (1973 a,

b, c) reported two new species of nematode Spirocamallanus from

Bangladesh. Rehana and Bilquees (1973) described Rhabdochona cavasius

n.sp from Mystus cavasius. Wouts (1973) reported some nematodes from

New Zealand. Bashirullah (1974) studied two new nematode species of

Camallanus from fresh water fishes of Dhaka, Bangladesh.

Hartwich (1974) published a detailed descriptions for the

identification of nematode parasites with a key. Jehan (1974) worked on

some Spirurid nematodes. Petter (1974) described the classfication of family

Cucullanidae. Schmidt, et al., (1974) studied the helminthes of North

Dekota and described nematodes from Paddle fish, Polyodon spathula. A

brief note has been published on nematode parasites by Sommerville and

Buzzell (1974). Amin (1975) and Arya and Johnson (1975) described new

nematode species from Indian waters. Chabaud (1975) reported a key to

identify the nematode parasites of the genera of the order Spirurida.

Moravec (1975) reconstructed the nematode genus, Rhabdochona with a

review of the species parasitic in fishes of Europe and Asia. Srivastava and

Gupta (1975 a,b,c) described in detail on nematode parasites of marine

fishes from Pentkota, Puri, Orissa including three new species of the genus

Camallanus. Zaidi and Khan (1975) worked on nematode parasites from

fishes of Pakistan.

Bilquees (1976) has given a list of parasites of fishes of Kinjar Lake,

Sind. Bilquees and Khanum (1976) described a new species of the genus

Rhaphidascaroides. Gupta and Garg (1976) worked on two new spiruroid

nematodes from marine food fishes in India. Moravec (1976) observed the

development of Rhabdochona phoxini. Srivastava and Gupta (1976 a,b,c)

published an account on nematode parasites including two new species of

the genus Camallanus and two new species of the genus Indocucullanus

from Pentkota, Puri, Orrisa.

Arya (1977) collected a new species of the genus Echinocephalus

from a fish and also published a key to the species of Echinocephalus. Arya

and Johnson (1977 a, b) collected two new species of the genus

Dujardinascaris and Rhabdochona from the fish Cybium guttatum. They

also reported a new species of nematode belonging to the genus

Dujardinascaris in 1978. Chaturvedi and Kansal (1977) published the check

list of Indian nematodes. Sood, et al., (1977) worked on some nematode

parasites of freshwater fishes from the Punjab state, India.

Arya (1978 a, b) described three new species of the genus

Camallanus and a new species of the genus Rhabdochona from Indian

waters. Chabaud (1978) has given a key to identify the nematode

parasites of vertebrates belonging to the genera of the super families

Cosmocercoidea, Seuratoidea, Heterakoidea and Subuluroidea. De, et

al., (1978) described some little known nematodes from Indian fishes.

Jackson, et al., (1978) studied on nematodes from fish market in the

Washington D.C. Moller (1978) described the effects of salinity and

temperature in the development and survival of nematode parasites.

Moravec (1978) collected the species of the genus Rhabdochona from

fishes of Czechoslovakia. Warren and Wilson (1978) studied parasitic

nematode Contracaecum in two species of fish.

Ahmed and Rahman (1979) studied pathogenicity of some

nematodes in flat fishes. Bilquees (1979) reported Rhabdochona

parastromatei n.sp from the fish Parastromateus niger of the Karachi

Coast. Gupta and Bakshi (1979) reported three new nematode parasites

from freshwater fishes of Lucknow. Margolis and Arthur (1979) worked

on the nematodes of fishes of Canada. Naidu (1979) has given a report

on the larval forms of the nematode belonging to Gnathostoma sp,

Contracaecum sp and Eustrongylides sp. from new piscine hosts of

Vidarbha region of Maharasthra State, India. Petter (1979) reported three

nematode parasites of fish in Malaysia. Salgado–Maldonado and Barqui

nalvarez (1979) described some nematode parasites from the fish Mugil

cephalus. Arya (1980) reported the larval forms of a nematode

Dujardinascaris cybii. Chubb (1980) described the seasonal occurrence

of nematodes in freshwater fishes. Review of Hysterothylacium and

Iheringascaris from the northern Gulf of Mexico were described by

Deardorff and overstreet (1980). Soota and Dey Sarkar (1980 a, b)

described three species of the nematode genus Cucullanus and given a

note on Lappetascaris lutjani from Indian marine fish.

Ahmed (1981) studied the nematode infection in fresh water fishes

of Bangladesh. Soota and Dey Sarkar (1981) worked on some nematodes

from Solan district, Himachal Pradesh, India. Much progress has been

achieved by Srivastava (1981). Bharathalakshmi (1982) reported in

detail on nematodes of Fishes, Reptiles, Birds and Mammals. Bilquees

(1982) reported new host records of nematodes Philometra lateolabracis

and Rhabdochona parastromatei. Deardroff, et al., (1982) reported

larval ascaroid nematodes from fishes near the Hawaiian Islands. Gupta

and Masoodi (1982) reported three nematode parasites and one known

nematodes from Kanpur, India. Gupta and Srivastava (1982) described

four new species of nematodes from the genus Rhabdochona from fresh

water fishes of India. William Eaton, et al., (1982) studied the nematode

infection in the northern anchovy from San Francisco Bay.

Gupta and Bakshi (1983) reported two new spirurids from the

intestine of the freshwater fishes of India. Gupta and Naqvi (1983 a, b)

reported two new species of the genus Indocucullanus and two new species

of the genus Paracucullanellus from freshwater fishes of Lucknow, Uttar

Pradesh. Gupta and Srivastava (1983) have given a brief account on

nematode parasites of fishes. Lakshmi (1983) studied the nematode parasites

of fishes of Andhra Pradesh. Naidu (1983) described some nematode

parasites of fishes of Vidarbha region, Maharashtra state, India. Siddiqi and

Khattak (1983) worked on some nematode parasites of fishes of North, East

and West Pakistan. Soota (1983) published nematode parasites of fishes in

Records of Zoological Survey of India. Gupta and Srivastava (1984 a, b)

reported some nematode parasites of marine fishes from Puri, Orissa.

Kumar, et al., (1984) described two new nematodes from cold water fishes

of Garhwal Himalaya. Siddiqi and Khattak (1984 a, b) collected some new

species of nematodes from fishes of North, East and West Pakistan. Wang

(1984) published three new species and given a list of parasitic nematodes

from vertebrates in Fujian Province.

Further work was done by Lushchina (1985) and Hamman (1986) on

nematode parasites. Ali, et al., (1987) described the nematode fauna of some

fresh water fishes from Tigris River, Baghdad, Iraq. Gupta and Garg (1987)

reported three ascaroids from marine food fishes in India. Gupta and Jaiswal

(1987) worked on some nematode parasites of vertebrates. Gupta and

Jaiswal (1988) erected some nematode parasites from fresh water fishes of

Lucknow. Haseen Fatima (1988) described the seasonal variation of

nematodes of some edible fishes of Karachi coast, Pakistan. Moravec and

Sey (1988) reported nematodes from fresh water fishes of North Vietnam.

Sood (1988) compiled the available information of nematodes in his book on

fish nematodes from South Asia. Munoz, et al., (1989) worked on some

cucullanid nematodes of eel Conger conger from the inshore water of

Valencia. Petter and Radujkovic (1989) worked on parasites of marine fishes

from Montenegro.

Ali, et al., (1990), Moravec and Rohde (1992) and Imam, et al.,

(1993) reported on parasitic nematodes of fishes. Moravec, et al., (1993)

collected some nematode parasites of fishes of the Parana River, Brazil.

Boomker (1994) did work on parasitic nematodes of fishes. Petter (1995)

worked on nematodes of fish from Paraguay. Moravec and Thatcher (1997)

described a new species of nematode Raphidascaroides brasiliensis in

thorny catfish from the Brazilian Amazon. Sardella, et al., (1997) described

a new species of Cucullanus in the fishes of South West Atlantic. Sudha

(1998) studied nematodes of marine and freshwater fishes of Visakhapatnam

coast. Ismen and Bingel (1999) studied nematode infection in the whiting

Merlangius merlangus euxinus off Turkish coast of the Black sea. Lakshmi

and Sudha (1999 a, b) described a new species Rhabdochona marina from

the intestine of Pempheris vanicolensis of Visakhapatnam and redescribed

Procamallanus mathurai.

Kirk, et al., (2000) worked on the effect of salinity on hatching,

survival and infectivity of Anguillicola crassus larvae under experimental

conditions. Lakshmi (2000) described a new parasite of the genus

Cucullanus from the fish Thalassinus. Ozturk, et al., (2000) studied

metazoan parasites of Pike (Esox lucius) from lake Uluabat, Turkey where

the third dominant parasite was the nematode Raphidascaris acus. Lakshmi

(2001) reported a new species Rhabdochona Indiana from the intestine of

Pempheris vanicolensis. Moravec and Huffman (2001) observed the biology

of Rhadochona kidderi texensis, a parasite of North American cichlid fish.

Lymbery, et al., (2002) worked on nematode parasites of inshore fish

species of South Western Australia. Crean, et al., (2003) described the anal

redness in european eels as an indicator of infection by the swimbladder

nematode, Anguillicola crassus. Doupe, et al., (2003) studied larval anisakid

infections of some tropical fish species from North West Australia.

Moravec, et al., (2003) described some nematode parasites from

fishes of central china. Steinauer and Font (2003) studied the seasonal

dynamics of the helminths of Blue gill, Lepomis macrochirus in a

subtropical region where Camallanus oxycephalus was the only helminth

that showed a distinct seasonal pattern.Vincent and Font (2003) worked on

seasonal and yearly population dynamics of two exotic helminths

Camallanus cotti (Nematoda) and Bothriocephalus acheilognathi (Cestoda)

parasitizing exotic fishes in Waianu stream, Oahu, Hawaii. Akther, et al.,

(2004) erected a new nematode species Goezia bangladeshi from

Bangladesh. Gaddy and Philip (2004) described anisakid infection in the

Mayan Cichlid fish. Kvach (2004) collected the far eastern nematode

Anguillicola crassus, a new parasite of the invasive round goby, Ncogobius

melanostomus, in the Baltic Sea. Lefebvre, et al., (2004) described the

impacts of nematode Anguillicola crassus from swimbladder of eel Anguilla

anguilla. Luo da min, et al., (2004) described Cucullanid nematode of

marine fishes from Taiwan Strait. Mandujano and Mojica (2004) presented

data on the seasonal variations in the occurrence and maturation of

Rhabdochona canadensis in its definitive host Notropis boucardi of the

Chalma River in the state of Morelos, Mexico.

Moravec (2004) described some aspects of the taxonomy and biology

of dracunculoid nematodes parasitic in fishes. Moravec and Genc (2004)

redescribed three nematode species of Philometra from the gonads of marine

perciform fishes of Iskenderun Bay, Turkey. Bilquees, et al., (2005) erected

nematode Pseudomazzia macrolabiata from fishes of Karachi coast.

Ercument, et al., (2005) worked on the seasonal variation and pathology

associated with helminthes Philometra lateolabracis (Nematoda:

Philometridae) and Trypanorhynch pleurocercoid, Grillotia sp (Cestoda:

Trypanorhynchia) infecting two Serranids of Iskenderun Bay (North east

Mediterranean Sea), Turkey. Ferrer, et al., (2005) described nematodes of

fish from Western Mediterranean sea. Merella, et al., (2005) reinstated

Philometra jordanoi a parasite of the fish Epinephelus marginatus. Moravec

and Ali (2005) erected two new species of Philometra from needle fishes in

Iraq. Moravec and Justine (2005) collected two anisakid nematodes from

marine fishes off New Caledonia including Raphidascaris nemipteri n.sp

from fish Nemipterus furcosus.

Fang and Luo da min (2006) described a new ascarid species in

elasmobranchs from Taiwan Strait. Moravec and Justine (2006) reported

three nematode species from elasmobranchs off New Caledonia. Moravec, et

al., (2006) collected nematode parasites of marine perciform fishes off New

Caledonia. Moravec, et al., (2006) erected a new nematode Procamallanus

from Pacific eels. Moravec, et al., (2006) worked on nematode parasites of

marine fishes off Corsica, France. Carball and Navone (2007) worked on

fishes in the North Patagonian Gulfs, Argentina. Martins, et al., (2007)

reported a new species Camallanus maculatus in an ornamental fish

Xiphophorus maculatus cultivated in Sao Paulo state, Brazil. George and

Lakshmi (2008 a, b) reported new host record for some nematodes from

marine fishes of Visakhapatnam, Andhra Pradesh. George and Lakshmi

(2009 a, b) reported new species Paragendria muraenesoxi from the coelom,

stomach and intestine of Muraenesox cinereus of Kakinada. Santos and

Moravec (2009) described Goezia spinulosa, a pathogenic parasite of the

fish Arapaima gigas. Sudhakar, et al., (2009) studied nematode parasites

from Sciaenids fishes of Parangipettai, south east coast of India. Puinyabati,

et al., (2010) worked on the seasonal occurrence of helminth parasites

Camallanus anabantis, Paraquimperia manipurensis and Astiotrema

reniferum infecting Anabas testudineus in Awangsoi Lake, Manipur.

Nadirah, et al., (2011) recorded three nematode species parasitized first time

in some marine fishes in Iraq. Moravec and Justin (2012) reported a new

ascaridoid nematode from lutjanid fishes off New Caledonia. Moravec, et

al., (2012) reported two species of Philometrid nematodes from marine

fishes off Japan. Shaheena and Zarrien (2012) described prevalence and

intensity of parasites in edible fishes landing at Karachi Fish Harbour,

Pakistan.

Fish is one of the best nutritious item recommemded by World Health

Organisation (WHO) in recent years. So the impact of fish diet has been

influenced among the people of India. Whereas in some of the states like

West Bengal, Orissa and Assam people treat the fish as one of the important

traditional food item. In view of the significance of fish health and the vast

diversity of parasites it harbours, the present study is undertaken to provide

adequate information on nematode parasites and their impact in different

species of edible fishes in region of Visakhapatnam. The present work gives

an information and caution to the pescetarians (fisheaters), which of the fish

species of both marine and freshwater are prone to nematode infection. The

seasonal distribution was also reported to understand the biodiversity of

nematode parasites from the marine fishes of Visakhapatnam.