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Sakalava fishermen and Madagascar Fish Eagles:enhancing traditional conservation rules to controlresource abuse that threatens a key breeding area foran endangered eagleRichard T. Watson a & Rivo Rabarisoa ba The Peregrine Fund's Project in Madagascar, B.P. 4113, Antananarivo (101), Madagascarb The Peregrine Fund, 566 West Flying Hawk Lane, Boise, ID, 83709, U.S.A.Published online: 19 Oct 2010.

To cite this article: Richard T. Watson & Rivo Rabarisoa (2000): Sakalava fishermen and Madagascar Fish Eagles: enhancingtraditional conservation rules to control resource abuse that threatens a key breeding area for an endangered eagle, Ostrich:Journal of African Ornithology, 71:1-2, 2-10

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2 Ostrich 71 ( 1 & 2)

Sakalava fishermen and Madagascar Fish Eagles: enhancing traditional conservation rules to control resource abuse that threatens a key breeding area

for an endangered eagle

Richard T. Watson & Rivo Rabarisoa’ The Peregrine Fund, 566 West Flying Hawk Lane, Boise, ID 83709, U.S.A.

‘The Peregn‘ne Fund’s Project in Madagascar: B.I? 41 13, Antananarivo (IOI), Madagascar

Watson, R.T. & Rabarisoa, R. 2000. Sakalava fishermen and Madagascar Fish Eagles: enhancing traditional conservation rules to control resource abuse that threatens a key breeding area for an endangered eagle. Ostrich 71 (1 & 2): 2-1 0.

Survival of the Madagascar Fish Eagle is threatened by human persecution and habitat loss. Of a global Madagascar Fish Eagle population estimated at 100 breeding pairs, the single most important concentration of ten pairs breeds on three adjacent lakes near the southern end of the species’ range along the western seaboard of Madagascar. Fishing on the lakes is the main livelihood of local Sakalava tribespeople who have harmoniously shared these important wetlands with fish eagles for centuries. In the last five years Peregrine Fund researchers have documented a massive influx of up to 275 seasonal migrant fishermen who abuse local traditional resource extraction rules.

The economic incentive to endure the hardship of migration to the lakes and camping on the lakeshore for the season is strong. In 1995 per-capita income from fishing was about $1 500 for the six month season, 7.5 times the national annual average. Fish stocks were rapidly diminished through the fishing season as catches diminished to the point where fishermen gave up fishing before the end of the season. The resilience of introduced lilapia sp. has so far ensured that stocks rebounded between fishing seasons. Fish stocks were at their lowest when Madagascar Fish Eagle nestlings fledged.

The most serious impact of fishermen may be on the lake-side forest, which was used as a source of dugout canoes and wood to fuel fish-drying fires. Up to 275 trees were cut for canoes in 1995 and up to 90 wood fires bumed for a total of about 1 1 1 500 hours to dry a catch of almost 6.9 million fish. To conserve this important breediig site we aim to prevent loss of fish eagle nesting habitat, increased nest site dishrbance, and reduced prey availability by working with community members and local leaders to enforce traditional resource use rules and find alternatives to unsustainable forms of resource extraction.

Watson, R.T. & Rabarisoa, R. 2000. Pkheurs Sakalava et Aigles @hem de Madagascar: relancer les regles traditionelles pour contr6ler l’abus de ressources m e n a v t la zone cle de reproduction d’un aigle en danger. Ostrich 71 (1 & 2): 2-10.

La survie de la Pygargue de Madagascar est menacee par la persecution humaine et la perte de I’habitat. A l’interieur d’une population globale estimee a 100 couples reproductifs, la seule concentration importante rassemble 10 couples se reproduisant au niveau de trois lacs adjacents situes pres de I’extremitC sud de l’aire de distribution de I’espece, qui longe la zone c6tiere ouest de Madagascar. La pCche sur les lacs est la principale source de subsistance de la tribu Sakalava qui a su vivre en harmonie avec les aigles en partageant ces milieux humides d’importance considerable au fil des siecles. Au cows de ces cinq dernitres annees, l’equipe du Peregrine Fund a enregistre une migration massive de plus de 275 pCcheurs saisonniers violant les regles traditionnelles d’exploitation.

Les lacs exercent un tel attrait economique que les difficultes de la migration et les conditions de campement au bord du lac sont endurees. En 1995, le revenu foumi par la pCche etait de $1 500 pendant les six mois de la saison, soit 7.5 fois la moyenne annuelle de revenue. La regknkration de l’espece introduite Elapia sp. assurait la recrudescence du stock de poisson entre les saisons. Ce stock de Poisson a connu une decroissance rapide durant la saison, la diminution du produit a poussk les pCcheurs a abandonner la pCche avant la fin de la saison. Le stock etait au plus bas au moment OG les jeunes aigles commencaient a voler.

L‘impact de l’existence de picheurs apparait plus skrieusement au niveau des forits autour du lac, qui sont sollicitees c o m e source de pirogues et de combustible pour le skchage du poisson afumer. En 1995, plus de 275 arbres ont ete abattus et plus de 90 feux de bois ont b d e pendant une periode totale de 11 1 500 heures pour faire secher 6.9 millions de poissons. Assurer la conservation de cet important site de reproduction requiert la prevention contre la perte ou la perturbation du lieu de nidification de I’Aigle picheur, et contre la diminution de la disponibilite du poisson. Nous collaborons dans ce sens avec les membres de la communautk et les responsables locaux afm de renforcer les regles d’utilisation des ressources et trouver des alternatives concernant leur exploitation informelle.

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7

I K.v: I

Figure 1. Map of lakes Befotaka, Soamalipo and Akerika showing villages and tempomry camps.

camping on the shore) have been controlled by traditional rules that were enforced by the tompondrano (“keeper of the lakes”), a traditionally inherited office.

Since The Peregrine Fund began conservation biology studies on the Madagascar Fish Eagle in 199 1 (Watson et al. 1993), the number of fishermen using Lakes Befotaka, Soamalipo and Ankerika has increased conspicuously, owing to influx of seasonal migrant fishermen from other parts of Madagascar. Coming with their families and camping on the lakeshore for six months, migrant fishermen are impacting the lakes and surrounding forest through fishing, wood collecting, tree cutting for pirogues (dug-out canoes) and fish-drying fres, and other subsistence activities. In the last five years, local traditions have been violated by seasonal migrants to the lakes, as well as by local residents, threatening the traditional balance of resource extraction and replacement and threatening the survival of the Madagascar Fish Eagle.

To help conserve the area’s natural resources for both the Madagascar Fish Eagle and the people who share them, we began documenting the types and extent of impact that migrant fishermen have on these resources in 1993. We counted the number of villages and temporary camps, censused the human population and assessed the extent of fishing through visits to camps and villages (Strzalkowska et al. 1995). Village dialogue surveys in 1994 showed that most of the resident and some of the migrant population perceived an over-use problem of the lake environment (Strzalkowska et al. 1995). The surveys also provided an understanding of local traditions, social customs and problems with their violation by fishermen.

This paper reports results of three surveys done during September 1995 (in the middle of the fishing season) that were designed to measure the impact of fishermen on the lakes, surrounding forest and fish eagle’s habitat. The pirogue survey documented the number

of fishermen active on the three lakes and measured their impact on large trees used for pirogue construction by counting pirogues, camps and fish-drying fires. The cut-tree survey measured the impact of fishermen on trees in the Tsimembo Forest surrounding the three lakes by estimating the density of cut-tree stumps, estimating the year’s cut and the use of the tree. The fishermen dialogue survey, conducted among inhabitants of temporary camps around the lakes, aimed to understand better the social and economic forces that were promoting the violation of traditional rules, and to begin to evaluate the possible impact of this level of resource extraction on both the traditional lifestyle of local residents and the habitat needed by the Madagascar Fish Eagle. With the understanding gained by these surveys and the work done in 1993 and 1994, we make recommendations for the control of resource use by both local and migrant fishermen, as well as guidelines to help conserve the Madagascar Fish Eagle.

METHODS Pirogue survey Three teams of two observers simultaneously counted all visible pirogues on Lakes Befotaka, Soamalipo and Ankerika during four count periods on four days from 1 1 to 15 September 1995. On three days, counts began about one hour after dawn at 07h30 and on one day the count began four hours after dusk at 22h00. Teams worked from boats and paddled or motored as fast as possible along the shores of each lake to ensure 100% visual scanning of the lake surface and its shoreline. Lakeshore length was divided equally between teams so that surveys were of similar duration. No team overlapped the area surveyed by another team, and where possible duplication of counts could arise due to pirogues moving from one team’s area to another, teams compared notes to eliminate this possibility. All pirogues seen were counted and their position on the lakes recorded

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4 Watson & Rabarisoa: Sakalavafishermen and Madagascar Fish Eagles

Ostrich 71 (I & 2)

on a 1 :40 OOO scale map to the nearest lo0 m. Pirogues were classified as either 1) in the water and used for fishing 2) in the water and used for transport or 3) on shore. Because pirogues can be transported between lakes, we used the maximum number counted on any single day as the total for the three lakes together, rather than taking the maximum number on each lake over the whole census period.

In addition to pirogues, all fishermen camps and rice-field camps were counted during one census and their positions recorded on the map. We counted all visible fires during the census that was done after 22h00, when visible fires could be assumed to be used for drying fish.

Cut-tree survey Two teams of two Peregrine Fund technicians (well trained individuals from local communities) conducted eight cut-tree transects of variable length from 18 to 21 September 1995. Teams arbitrarily chose a starting point on the lake’s edge, walked 20 m into the forest and then tried to find all signs of cut trees while following the shore profile for 2.2- 3.5 h. All cut-trees were identified to species if possible, diameter measured across the cut surface, and their distance from shore estimated by pacing. Technicians estimated the year in which each tree was cut based on their experience of decay rates for each species, and they used their knowledge of local use of trees plus the diameter of the cut-tree to infer its use. Survey routes were plotted on a 1 :40 000 map as the survey progressed, and survey area was estimated assuming a 5 m width transect.

Fishermen dialogue survey Temporary fishing camps were visited by Peregrine Fund technicians each afternoon when daily wind conditions forced ffihermen to return to their camps. The technicians were residents of the region who were familiar with local people and traditions. A camp headman, usually the man of the family, was chosen for discussion which covered a variety of topics including the goals of The Peregrine Fund and the nature of our work. Survey questions (Table 1) were inconspicuously asked by one technician during general discussions by all technicians, and responses were noted by a second who sat in the background. Surveys often took three or four hours of discussion, even though the questions could have been answered in 15 minutes of direct questioning. We felt it necessary to conduct surveys in this way so as to put people at ease and elicit unbiased answers. It also gave technicians the opportunity to collect some direct observational data, such as the number of people present, number of pirogues and number of fish-drying fires (Table 1).

Table 1. Fishermen dialogue survey questions.

~

1. 2. 3. 4. 5. 6.

I.

8. 9. 10. 1 1 . 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22.

Question Asked (A) or Observed (01

Location of camp (map x,y co-ordinates) Name of camp Number of fishermen who use the camp Origins of fishermen When did they begin fishing How many pirogues do they have, and how many are new Catch per person per day at the beginning of the season and now Method of preparation of fish Kind of wood used and method of finding it Number of fires in each camp How long does it take to dry fish How many fish can be dried at one fire Who buys fish (their origin) Where do they take ii What is the price and barter value of fish What is the length of your nets What is the mesh size How many nets do you have How many dogs live in camp Where do you find wood for new pirogues How long will you stay here How do you know these lakes for fishing

0 A A A A

A

A & O A A 0 A A A A A A A A A A A A

RESULTS Pirogue surveys Each of three daytune surveys lasted an average 2.33 + SD = 0.42 h on Lake Befotaka, 1.75 + SD = 0.07 h on Lake Soamalipo and 2.67 + SD = 0.07 h on Lake Ankerika. The maximum number of pirogues counted in one day on all three lakes combined was 275 on 14 September. They were categorised as follows: 132 fishing pirogues in the water, 120 pirogues on shore and 23 pirogues transporting people, dried fish, or other goods. The maximum number of fishing pirogues counted in the water was 15 1 on 15 September, or 55% of available pirogues. Pirogues were divided between the three lakes as follows: L. Befotaka = 121 or 3 1.4 piroguedkm2, L. Soamalipo =

120 or 24.7 pirogues/lan2, and L. Ankerika = 34 or 11.0 pirogued km2 (lake surface areas from Bousquet & Rabetaliana 1992).

The lowest count was 106 pirogues counted during the night of 11 September. The night count was least reliable because of limited visibility which reduced our travel speed and limited the number of pirogues seen. Although most fishermen fish through the night, finishing their work from dawn to about 4 or 5 hours after dawn, night counts were abandoned as being ineffective. Morning counts were used instead despite the fact that they may underestimate the number of active fishermen.

We counted 42 temporary fishermen camps and five permanent villages (Befotaka = 25, Soamalipo = 15, Ankerika = 7) and 53 temporary rice-field camps (Befotaka = 32, Soamalipo = 19, Ankerika = 2) located on the lakeshore (Figure 1). During the one night census, we counted 32 drying fires burning after 22h00.

Cut-tree survey Eight variable length transects covered areas from 2 000 mz to 14 000 m2 (Table 2). The density of cut-trees in each transect varied from a minimum of 15 treesha to 290 treesha (Table 2). Nineteen cut-tree species were identified (Table 3). Cutting trees to fuel fires affected 13 species and was the most frequent use of trees. Cutting trees for pirogue (dug-out canoe) construction was the second most frequent use of trees, but was limited to four species (Table 3). The numbers of cut-trees in 1989 to 1991 were low (3 to 7 each year, Table 3), began increasing in 1991, and reached a peak in 1995 that was nearly 50 times greater than the average of 1989 to 1991 (Table 3). Trees used for pirogue construction were usually large in diameter (mean = 61.3 cm, Table 4) and averaged 139.8 m from the shoreline. Trees used for firewood averaged 18.4 cm diameter and averaged 65.2 m from the shore. The distance of pirogue and firewood trees from the shore did not change significantly through the years (Table 5) .

Fishermen dialogue survey Eighteen temporary fishing camps and one village (Antsakoramby) were visited from a total of 42 temporary camps and five villages in existence from 13 to 23 September 1995 (Figure 1). Not all temporary camps were visited due to time constraints, but we felt that reasonable extrapolations could be made from the 43% that were visited. Villages were not surveyed because much information already existed about their inhabitants (Stnalkowska et al. 1995).

Migrants came from 14 different villages, the most distant of which was Antsalova (50 km from the lakes, Figure 2). Camp inhabitants included 132 fishermen and 261 family and others (buyers), giving a total migrant population of around400 people in surveyed camps. Assuming all temporary camps to have similar composition of fishermen and their families, then the total migrant population, including camps not surveyed, was about 307 fishermen and 607 family and others, totaling 914 people.

All migrants reported that they amved at the lakes during June to begin fishing at the beginning of the open season, and normally expected to stay an average of 5.6 months. In 1995 however, most began fishing only when the season opened, later than usual, at the end of June, and anticipated staying on average 4.4 months.

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2005 Watson & Rabarisoa: Sakalavafishermen and Madagascar Fish Eagles

Table 2. Survey statistics and cut-tree density in lake shore forest around Lakes Befotaka. Soamalipo, and Ankerika in 1995.

5

~

Survey No.

I 2 3 4 5 6 7 8

Date Team members ~

I8 Sept 18 Sept 19 Sept 19 Sept 20 Sept 20 Sept 21 Sept 21 Sept

JIG LIL LIL JIG LIL JIG LIL JIG

~

Survey duration (h) Area (m’) Cut-tree density ( h a )

3.0 6 000 60.0 3.5 8 000 I 16.3 2.5 2 000 290.0 3.0 14 000 15.0 2.5 1 1 000 92.7 2.5 12 000 29.2 2.5 6 000 88.3 2.2 6 000 43.3

When asked if the fish size had diminished over the fishing season, fishermen in four camps said “yes”, admitting to violating local traditional laws by using a smaller mesh size net to catch smaller fish, while most fishermen (n = 14 camps) replied that size had not changed but the catch had diminished. Fishermen counted their catch in units of 3 fish, called a tas, but for the purpose of reporting results, we have translated units to individual fish. At the beginning of the fishing season they caught an average range from 192 to 255 fish per day per fisherman. By our survey in September, about two months into the season, reported catch rates had dropped to 99 to 137 fish per day per fisherman. Fishing nets were reported to be “4 finger” (8 cm) mesh size (n = 17 of 19 camps) to “3 finger” (6 cm) mesh size (n = 6 of 19 camps). Net lengths were generally given as a range of lengths from 50 m to 100 m and 1 m deep. The total number of nets reported was 100.

The average number of fish-drying fires was 4.6 per camp and the total number counted in surveyed camps was 87. We estimated by extrapolation that 202 fires existed around the lakes. Fish were dried in front of fires in units, known as salaza, of three fish attached to sticks. Fishermen’s estimates of the time needed to dry a salaza of fish averaged 1.12 h, and each fire dried an average of 23 salaza (69 fish) at any one time. Most fishermen preferred two tree species as a source of firewood, Cedre lops ispe i (locally called Katnfay, n = 13 camps) and Dalbergia sp. (locally called Magnary, n = 14

camps), whereas fishermen in five camps said they were not selective about wood used, three camps also used Securinegu (locally called Hazomena or Soalafiky), and one used the wood of Tamarindus indica. Sixteen of the camps reported using only dead wood for their fires; one reported cutting live trees to burn the wood 2-3 weeks later.

Fish were sold for cash or bartered for goods, such as rice, coffee, oil, and batteries (Table 6). Fish buyers came from 11 villages or cities (Table 7), mostly from within 100 km of the lakes but individuals were reported from as far as Antananarivo (minimum three days drive and about 1 000 km by road) and Fianarantsoa (minimum 2.5 days drive and 700 km). Fish were carried by buyers to commercial centres for resale, where they may be consumed or transported M e r (Table 7). Belo-Tsiribihina was the most fkquently reported destination, probably because it is the first significant market and population centre on the route out of the lakes region.

We counted 134 pirogues at camps (49% ofthe 275 pirogues visible on the lakes during pirogue counts) of which 28 were obviously new. Pirogues crack and rot at rates depending on the wood species used for construction, but favoured species of soft wood last only six months to one year.

When asked how they knew of these lakes and the fishing opportunity there, residents of nine camps reported some prior

Table 3. Detection frequency of each cut-tree species, estimatedyear cut, and probable use.

Estimated year cut

Species 1989 1990 1991 1992 1993 1994 1995 Use

Adenia sp. Albizia bernieri Alleanthus greveanus Bridelia pervilleanum Cedrelopsis grevei Commiphora sp. Dalbergia sp. Diospyros sp. Givotia madagascariensis Grewia sp. Gyrocarpus americanus Hazomalania voyroni Mascarenhasia lisianthrjlora Poupartia silvatica Rhopalocarpus lucidus Securingea perrieri Stereospermum euphrioides Tamarindus indica Terminalia sp. Unknown 1

1

1

1

1 7

1 2

1 I 1

1

1 1

1

1 1

1

1 29

3

1

1

21

22 2

6 10

2

1

12 4

2

58 1

62 1

19 2s

10 1

5 5 12 15

Unknown Fire Fire Fire Fire unknown

Fire Fire Pirogue, tire Fire Pirogue Pirogue Fire Pirogue Fire, paddles, hut Fire Fire Fire Unknown Fire Probably

Total 3 1 5 17 12 81 239 Total 424

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6 Ostrich 71 (1 & 2) Watson & Rabarisoa: Sakalava fishemen and Madagascar Fish Eagles

Table 4. Diameter at cut and distance to shore of trees used byjishermen on Lakes Befotaka. Soamalipo and Ankerika.

Use n Diameter at cut, em Distance from shore, m ~~ _____

Mean SD Mean SD

Pirogue construction Pirogue paddles Firewood Traps Planks Honey collection Medicine House building Unknown

45 61.3 5 12.8 316 18.4 10 21.9 2 48.5 2 28 1 22 15 6.1 27 18.4

12.1 10.7 9.3 11.7 11.5 2

1.2 9.8

139.8 74.0 107.0 141.6 175 125 30 81.3 70.0

50.5 64.1 65.2 45.9 25 25

11.3 37.0

knowledge based on residence in the region, seven camps reported having been told by others (rumour) while three were not asked.

Resource extraction estimates Using our data and making several assumptions, we made rough estimates of the number and weight of fish extracted from the lakes each season, the income derived from fishing, and the amount of time fires must burn to smoke and dry all the fish. The last estimate was used to gauge the impact ofwood collecting on the surrounding Tsimembo Forest and availability of nesting habitat for Madagascar Fish Eagles.

We assumed that the total number of migrant fishermen on the lakes was constant at 307 through the fishing season, and there was a linear change in catch rates from the beginning of the season in June through September to the end of the season in November. We calculated the maximum and minimum daily catch rate for all fishermen collectively by multiplying the number of fishermen (307) by the maximum (292) and miniium (256) reported daily catch per person at the beginning of the season and at mid-season (15 September, max. = 137 fish/ person, min. = 99 fish/person). Then, assuming a linear change in catch rate over time, the relationship between time (days) and total daily catch (fish per day) was described by the regression equation: total daily catch = 84 578.5 + (-460.5 x time), Z 4 . 9 2 , P<0.05, de2 . Using this equation, we estimated that total catch from the three lakes during an average 5.6 month fishing season was 7 671 930 fish, or about 1 918 metric tonnes assuming each fish weighed an average of 250 g.

The number of hours in front of a fire required to dry the daily catch (fire-hoursld) was estimated by dividing the reported daily catch by 3 (salaza unit) and again by 23 (average number ofsalaza per fire) and multiplying by the average time to dry a salaza of fish (1.12 h). Using the maximum and minimum reported catches

Table 5. Mean and standard deviation of distance to shore in each year for trees cut for pirogue construction and jire fuel.

Estimated year cut Pirogue construction Firewood

Mean distance to shore (m)

1989 1990 1991 20 1992 106.7 1993 147.5 1994 170.0

SD II Mean SD

0 90 10.0 0 110 48.6 I 46 97.5

70.4 3 91.8 71.0 65.3 4 98.8 72.5 33.2 4 84.3 57.1

n

2 6 4

12 56 65

___

1995 132.9 50.6 38 119.6 63.4 170

at the beginning of the season (1 June) and mid-season (1 5 September) and assuming a linear change in daily catch rate through the season, then the relationship between total fire-hourslday (for all fishermen collectively) and time (days) through the season was described by the linear regression equation: total fire-hourslday =

1372.9 + (-7.475 x time), $ = 0.92, P<0.05, d e 2 . Using this equation, we estimate the total number of fire-hours in a 5.6 month season was 124 528 hours. If fishermen maintained 202 fires during the fishing season, then each fire burned for 6.3 to 7.2 h/day at the beginning of the season and dropped to 2.4 to 3.4 Wday at the end of the season as the catch rate fell. This corroborates our observation at mid-season that fishermen typically spent the afternoon and evening (4-6 h) drying fish by fires.

We do not know how much wood a 69 fisWh fire consumed in one hour. A rough estimate was made as follows: a 69 fisWfire must have a circular area sufficient to stick 23 salaza (stick of three fish) into the ground side by side. Each salaza was as wide as the length of a Zilapia spp. fish, about 25 cm. Therefore, a fire must have a circumference of at least 5.75 m to dry 23 salaza, and an area of 2.63 mZ; it must be a large fire, probably taking two 1 x 0.3 m logs each 3 hours. Over a season we estimated about 83 019 m of 0.3 m diameter log was burnt by migrant fishermen.

Economic impact of fishing The price of smoked and dried fish varied with demand. At the time the survey was conducted, mid-season in September, the price for one tas (three fish) varied from 750 to 1 000 Fmg (Francs Malgache) (Table 6). Prices at the beginning and end of the season were 500 Fmgltas. Assuming an average price of 750 Fmgltas, then the annual harvest of fish was worth 1 917 982 500 Fmg or about U.S. $479 495. This represents about 6 247 500 Fmg (U.S. $ 1 562) per fisherman per season. Since the average annual per capita income country-wide is $225-250, an income eight times greater for six months work is a substantial economic incentive to fish. Thus, the three lakes are an important source of income to the migrant and local population.

The buyers who transported fish from the lakes to other commercial centres, such as Belo-Tsiribihina and Antananarivo made an unknown but probably substantial amount of profit. A rough idea of profit based on the price of a tas of fish in Antananarivo at the time, 7 000 Fmg, indicated an almost tenfold gross income to intermediaries. Transport and other overhead costs were unknown.

DISCUSSION Pirogue survey The number of fishermen on the lakes has increased dramatically since 1991 when we observed about 30 fishing pirogues active at any time (pers. obs.). Zarasoa (1995a,b) reported 276 men inhabiting the vicinity of the lakes in 1993 and Strzalkowska et al. (1 995) reported 364 inhabitants (including women and children) in 1994. Because the adult population is composed of fishermen and their families, we did not know how many adults actually fished the lakes. By counting the number of pirogues visible on the lake surface and shoreline in 1995 we obtained a fairly precise estimate of the number of fishermen fishing the lakes that can be compared over time using the same method. In 1995 there were at least 275 pirogues available for fishing on the three lakes. We never observed more than one man in a pirogue that was being used for fishing. Therefore, assuming one fisherman per pirogue at least 275 fishermen fished the lakes during our survey period.

Fishermen began fishing around sunset when the afternoon wind and waves on the lakes diminished and continued until the wind and waves increased again at about noon the following day. Our surveys were conducted from 07h30 to about lOhOO when fishermen were concluding their day’s work. Thus, about 55% of the 275 pirogues were active during surveys which were typically towards the end of the fishing “day”.

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2000 7 Watson & Rabarisoa: Sakalavafishermen and Madagascar Fish Eagles

R- do Bemanha

! *Am-

Figure 2. Regional map of lakes Befotaka.Soamalipo andhkerika showing villages that were a source of migrant fishermen.

A pirogue’s life when made from the most popular soft wood (Givotia madagascariensis. Gyrocarpus americanus) is short, from 6 months to 2 years (Zarasoa 1995a; L. Kalavaha pers. comm.). A pirogue becomes unusable when it cracks or rots. A fisherman will typically use a new pirogue each fishing season and it takes one tree to make one pirogue. Thus, we infer that in 1995 at least 275 large trees were cut to build pirogues. Pirogues are heavy and difficult to transport, so most (but not all) were cut from forest surrounding the lakes.

In 1994 we counted 20 villages and temporary camps around the three lakes: five camps and one village on Lake Befotaka, three camps and three villages on Lake Soamalipo, and four camps and four villages on Lake Ankerika (Strzalkowska et al. 1995). In 1995

Table 6. Cash or barter value offresh or smoked and driedjish. September 1995, at Lokes Befotaka. Soamalipo and Ankerika. I kapoaka = approximately I cup. Fmg = Francs Malgache.

Number of fish Money orgoods

1 tas = 3 fish, smoked & dried 750 to 1 000 Fmg I kapoaka (cup) rice 2 rice cakes

1 kapoaka dried beans 6 bananas 600 Fmg 1 kapoaka sugar 2 D cell batteries 1 kapoaka coffee 1 litre of alcohol 1 radio-cassette recorder

I tas = 3 fish, fresh 3 tas = 9 fish, smoked & dried

9 tas = 27 fish, smoked & dried 8 to 10 tas = 2&30 fish, smoked & dried

8 to 10 tas = 24 fish, smoked & dried 700 tas = 2 100 fish, smoked & dried

the number of fishermen camps and villages was 47. This increase of 135% was due entirely to seasonal migrant fishermen camping on the lakeshore. The greatest impact of the families living in the camps was on the forest resources in the immediate vicinity of the camp where campers cleared trees and brush for the camp, cut trees for firewood and hut construction, stripped bark off trees for making baskets and rope, trapped wildlife for food, and incidentally disturbed breeding or foraging wildlife.

Cut-tree survey The cut-tree survey showed that the rate of cutting trees for pirogues, firewood and other uses has increased dramatically in the last two or three years, and parallels the increase in numbers of temporary immigrants who fish on the lakes seasonally. The impact is greatest in the forest-lake ecotone region simply because it is the most accessible part of the forest to fishermen who camp on the lakeshore and work on the lake. Habitat ecotone has been shown to be important for maintaining a high diversity of life, and is very important for sustaining life processes in adjacent habitat types.

Of 23 tree species used for nesting by the Madagascar Fish Eagle (Watson et al. 2000) six species were cut for use by local people (Table 3): Alleanthus greveanus, Cedrelopsis grevei, Poupartia silvatica, Stereospermum euphrioides, Tamarindus indica, and Terminalia sp. Madagascar Fish Eagles nested from 0 to 900 m from water (mean = 112 m, SD = 177, n = 52, Watson et al. this volume) which coincides with the zone of greatest use by fishermen. Madagascar Fish Eagles typically nested in the tallest (and therefore widest in diameter) trees in an area, so trees cut by fishermen for pirogues are probably the most likely to cause an immediate loss of suitable nest trees for fish eagles. According to this survey, only Poupartia silvatica was used by both eagles for nesting and fishermen for pirogue construction. However, we predict

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Ostrich 71 (1 & 2)

Table 7. Frequency of reported origin of f s h buyers and destination of soldfish.

Village or town name, road distance from lakes Frequency of buyers reported Frequency of destinations reported

Ambereny, 10 km 1 1 Antananarivo, 1 000 km 1 4 Antsalova, 50 km 10 3 Antsirabe, 900 km I Bejangoa, 15 km 2 Bejea, 15 km 2 Bekopaka, 60 km 4 1

Bepilopilo, 25 km 1

Belo-Tsiribihina, 150 km 1 13 Masoarivo, 12 km 3 Morondava, 250 km 5 5

Soatana, 12 km 9 1

Tamatave, 1 500 km 1

Tsiromandidy, 450 km 1 5

that loss of small specimens of suitable nest-tree species to fishermen for frewood will cause a loss of suitable eagle nesting habitat in the future as large specimens die. In addition, two species used by nesting eagles, Alleanthus greveanus and Cedrelopsis grevei, were favoured for pirogue construction (Zarasoa 1995b) but were not recorded as being cut for pirogues during our survey. This may be because no specimens that are large enough for pirogue construction remain in the vicinity of the lakes, possibly indicating a previous, and therefore unmeasurable, impact of tree cutting on nest-tree availability for fish eagles.

If human use of the lakes and forest resources remains at current levels or continues to increase, we predict an ultimate shortage of nest-trees available for breeding Madagascar Fish Eagles and consequently, very serious negative impact on the survival of this species.

We documented one case of a nest-tree being cut by fishermen and many cases of trees being cut within 50 m of an occupied nest tree. The effect of disturbance by fishermen cutting trees or collecting firewood near breeding birds may be significant but difficult to quantify (e.g. McGarigal etaf. 1991). Studies on Bald Eagles in North America show that human activity within 50 to 990 m of breeding or hunting eagles had a significant negative impact on the birds (e.g. Fraser 1985; Fraser et al. 1985; McGarigal et al. 199 I ) .

The negative impact of tree cutting may be more immediate for other endemic species in the region, such as a variety of birds and lemurs which depend on target trees for shelter and food. For example, a high conservation priority lemur species, Decken’s Sifaka Propithecw v e m a u i deckeni (Mittermeier et al. 1994), is abundant in the forest around the lakes. Another large and abundant lemur in the forest, the Red-Fronted Brown Lemur Eulemurfirlvus ru jk , has adayrangeof 125to 150m, homerangeof0.75to l.Oha(Mittermeier et al. 1994) and would be dramatically affected by the loss of trees at the rate measured in this study ( 15 to 290 trees/ha, Table 2).

Fishermen dialogue survey It is important to evaluate the accuracy of our resource extraction estimates by considering the various sources of error and bias. We counted 132 fishermen and 134 pirogues in 43% of known fishing camps, which, as would be expected, is very close to one pirogue per fisherman. Assuming a similar occupancy of the remaining 57% of camps, we calculated the total number of migrant fishermen was 307. Therefore, we predict that the total number of pirogues on the lakes would be at least 307 for migrants, plus those of resident fishermen. However, we counted a maximum of 275 pirogues from 11 to 13 September, a few days before our camp survey. This

difference will be due to two sources of bias. First, pirogue counts may have underestimated the number of fishermen because it is possible that not all pirogues were visible. However, we believe this error to be minimal since pirogues are readily seen on the lake and its shores, and pirogues were rarely hidden among vegetation. Second, our assumption that the 24 camps not visited had the same occupancy as those that were visited is a more likely source of error. It is possible that technicians chose the larger, more visible camps to visit first, thus causing an overestimate of the total migrant fishermen population. Because this is a likely source of error it is important to recalculate our estimates of total catch using a minimum of 275 fishermen (89.6% of previous estimates) based on pirogue counts and assuming that all available pirogues were used once per day to net an average catch of fish. Per capita income will not be affected by these biases.

Thus, the linear regression model describing the relation between catch (fish/day) and time (days) through the season was: catch = 75 762 + (412 x time), r 2 = 0.92, P<0.05, df= 2. Based on this model the total catch in a 5.6 month season would be 6 872 166 fish, or about 1 718 metric tomes. The linear regression model describing the relation between time needed to dry fish (fire-hours) and time (days) through the season was: fire-hours = 1229.7 + (-6.7 x time),? = 0.92, P<0.05, df = 2. Based on this model the total number of fire- hours in the season would be 1 11 533 fire-hours, or about 74 355 m of logs. We believe the above estimates more accurately reflect current levels of resource extraction on the lakes during the fishing season, while the estimates given in the results section may be somewhat overestimated.

The assumption that all the fishermen we counted fish all season may not be true. To determine numbers of fishermen more accurately, counts of either fishermen or pirogues would have to be done at least three times during the fishing season, e.g., during the first week, middle week, and last week, and preferably more often than that. Regression of these counts would provide a mean and confidence limits.

We assumed that all fishermen fished seven days per week for the entire season. This may overestimate the number of fishermen- days because it ignores days off for rest and repair of equipment. However, by using the count of pirogues active on the lakes to estimate fishermen effort we would include the effect of fishermen “down time”. We believe pirogue counts to be accurate, they are quicker to achieve than counts of fishermen in camps, and can be done on random days throughout the fishing season. Pirogue counts would be useful for estimating total resource extraction rates for the lakes, but they do not differentiate between the relative effects

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ofmigrant and local fishermen. If needed, concurrent counts ofthe relative abundance of local and migrant fishermen wouldbe needed to distinguish their relative impact.

The assumption that there was a linear decrease in catch rates through the season may not be true and relying on fishermen’s estimates of their own catch may not be reliable. It would be preferable to count catches of a sample of about 10 fishermen on each lake at three points in the season, beginning, middle and end, or more often. Regression of these figures would provide a mean with confidence limits.

We used a mean estimate of the time that it takes to dry a fish that was based on fishermen’s opinions. A more accurate estimate with confidence limits could be derived by measuring the amount of time a sample of fishermen (about 30) leave fish in front of the fire. At the same time, the observer should count the number of fish per fire to derive a mean with confidence intervals, rather than relying on the fishermen’s estimate.

The amount of wood needed to keep a fire burning for 1 h of suitable size for fish-drying was unknown. For the purpose of this paper, we made a guess based on experience, but it would be preferable to measure the amount of wood needed, from a sample of 10 fires for each wood species and provide a mean with confidence limits.

CONCLUSION The forest/lake ecotone is habitat for the endangered Madagascar Fish Eagle as well as other endemic species of conservation concern (e.g. Decken’s Sifaka). The numbers and rate of increase of fishermen and their camps is cause for concern because of their impact on the forest surrounding the three lakes. This study revealed extremely high rates of resource extraction imposed on the lakes and surrounding forest by migrant as well as local fishermen. Based on our observation of forest destruction around the lakes, current rates of extraction are undoubtedly not sustainable, and may begin to impact the breeding and survival of Madagascar Fish Eagles in the next few years. It probably already has impacted the life-style of local fishermen who want to preserve their traditional rights to the resources in the vicinity of their homes.

This study shows the urgent need to limit the rates of resource extraction to levels that can be sustained by the lakes and forest without impacting the survival of endangered Madagascar Fish Eagles and without negatively impacting the life-style ofthe resident fisherman population. The important limiting resources are fish from the lakes and wood from the forest.

Of primary concern to locally resident fishermen is the impact of migrant fishermen on fish stocks, annual yield, and per capita income. We do not know what impact current rates of fishing have on the fish population, except that catch rates diminished through the fishing season, to levels where fishermen “gave-up” after four or five months for lack of catch. Until 1995, catch rates had always recovered by the beginning of the next fishing season due to the resilience of Zilapia spp. to cropping, but catch rates in 1996 have remained low at 12-20 tuslfishermadday (pers. obs.). Catch rates must be carefully monitored to detect signs of an irrecoverable population crash. Current levels of fishing would seem to be above a maximum rate sustainable by the fish population over the entire fishing season. Continued fishing at these rates have resulted in individual fishermen giving up sooner, and reduced per capita incomes per season.

The forest surrounding the lakes is probably the most important limiting resource because growth and replacement rates of trees is much slower (perhaps thousands of times slower) than that of the fish population. It is the impact of fishermen on the forest that is of greatest concern, not only for local people but also the fish eagle that nests in the forest, and a wide variety of endemic and vulnerable

terrestrial animals that live in it. Extraction ofwood from the forest, especially the cutting of live trees must be limited to sustainable rates, in which extraction equals replacement.

RECOMMENDATIONS We believe that, with some minimal assistance, the local resident community can achieve conservation of the lakes and surrounding forest for three reasons. First, it is in their own economic interest to do so. Second, they are building on a tradition of resource control that has existed for decades, possibly centuries. Third, we have given them the information needed to justify conservation, for themselves and the endangered Madagascar Fish Eagle.

Based on our results, in early 1996 we recommended enforcement and self-adherence to existing traditional rules, such as a minimum mesh size on nets of 8 cm, a ban on the use of seine or trawl nets, and a ban on camping on the lakeshore. We suggested adopting a new rule, that the cutting of live trees should be banned. Further, we recommend either limiting the number of fishermen (e.g. to resident population only) who can use the lakes and surrounding forest, or introducing to fishermen viable alternative methods for fish preservation (e.g. drying fish in solar ovens) to reduce tree cutting for firewood and introduction of viable alternatives to pirogues (e.g. fibreglass canoes) to reduce tree cutting for construction. We proposed three alternatives for achieving limitation of resource extraction that the local population should consider, one of which should be adopted as soon as possible:

Severely limiting the number of fishermen (e.g. we suggest 20 fishermen per day, but further study or monitoring is essential) who fish the lakes and collect wood from forest around the lakes so that natural wood replacement equals extraction; or

Less severe limitation of the number of fishermen (e.g. 5&75/ day, but W e r study or monitoring is strongly recommended) provided that alternative sources of wood for fish-drying and pirogues are used, such as forest more than 1 km from the lakes and a planting programme to replace extracted trees; or

Least severe limitation of the numbers of fishermen (e.g. 15& 200/day, but fish population monitoring is essential) who fish the lakes provided that no wood is collected for fires or pirogues because fishermen use alternatives such as solar-ovens for drying or alternative ways for preserving fish, and fibreglass canoes.

As a reasonable precaution based on the recovery plan for the similar, and better known, Bald Eagle Haliaeetus feucocephalus (Crier 1983), we recommend adoption of ‘‘primary management zones” in which wood collecting, camping or other human activity is banned within 100 m of nesting Madagascar Fish Eagles (May through November). Lastly, we recognize the need for public awareness and enforcement of the existing nationally protected status of fish-eagles and their nests, and have offered assistance by The Peregrine Fund technicians to extract eagles accidentally caught in fishermen’s nets.

These rules, and the limitation of the numbers of fishermen andor the adoption of alternative sources of boats and fish drying methods, must be supported and enforced collectively by local people, Direction des Eaux et For&, and Department of Fisheries. Local people have expressed their desire to limit the number of fishermen on the lakes and have ideas on how this may be achieved by enhancing and enforcing traditional rules (dina). However, they need help with enforcing rules that will require patrolling and checking permits and activity. A small motorised boat, fuel to run it, and maintenance will be required for this purpose. These recommendations should help conserve the Madagascar Fish Eagle and many other threatened species, as well as conserve the natural resources on which local people depend.

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ACKNOWLEDGEMENTS We thank technicians Jules Mampiandra, Gaston Radelison, Loukman Kalavah and Eloi (Lala) Fanameha, and other team members Chris Watson, Russell Thorstrom, Carter Ong, and Jeanne Ernst. We thank the Direction des Eaux et For& (DEF), Association National pour le Gestion des Aires Protegees (ANGAP), members of the Tripartite Commission, Bemaraha Project and UNESCO for collaboration.

REFERENCES Bousquet, B. & Rabetaliana, H. 1992. Site du patrimoine mondial des Tsingy de Bemaraha et autres sites d’interet biologique et ecologique du fivondronana d’htsalova. Paris: UNESCO

Fraser, J.D. 1985. The impact of human activities on Bald Eagle populations - a review. In: Gerrard, J.M. & Ingram, T.M. (eds.). The Bald Eagle in Canada. Proceedings of Bald Eagle Days, 1983: 68-84. Apple River, Illinois: White Horse Plains Publishers and The Eagle Foundation.

Fraser, J.D., Frenzel, L.D. & Mathisen, J.E. 1985. The impact of human activities on breeding Bald Eagles in north-central Minnesota. J. Wildl. Manage. 49: 585-592.

Grier, J.W. 1983. Northern states bald eagle recovery plan. Denver, Colorado: US. Fish and Wildlife Service Reference Service.

Langrand, 0. & Meyburg, B.-U. 1989. Range, status and biology of the Madagascar Sea Eagle Haliaeetus vociferoides. In: Meyburg, B.-U. & Chancellor, R.D. (eds.). Raptors in the modem world 269- 277. Berlin, London & Paris: WWGBP.

McGarical, K.,Anthony, R.G. & Isaacs, F. B. 1991. Interactions of humans and Bald Eagles on the Columbia River Estuary. Wildl. Monogr. 115: 1-47.

Mittermeier, R.A., Tattersall, I., Konstant, W.R., Myers, D.M., & Mast, R. 1994. Lemurs of Madagascar. Washington, D.C.: Conservation International.

Rabarisoa, R, Watson, R.T., Thorstrom, R & Berkelman, J. 1997. Status of the Madagascar Fish Eagle Haliaeefus vocifemides in 1995. Ostrich 68: 8-12.

Stnalkowska, S., Kalavah, L. & Mampiandra, J. 1995. Village dialogue: gaining information through participatory discussions. In Watson, R.T. (ed.). Madagascar Project, Wetlands Conservation Project, Progress Report 11, 1993 and 1994. Second Edition: 81- 132. Boise, Idaho: The Peregrine Fund.

Watson, R.T., Berkelman, J., Thorstrom, R., Rabarisoa, R. & Watson, C.RB. 2000 Nest site description of the Madagascar Fish- Eagle Haliaeetus vociferoides. Ostrich 71 (1 & 2): 335- 340.

Watson, RT., Berkelman, J., Lewis, R. & Razafindramanana, S. 1993. Conservation studies on the Madagascar Fish Eagle Haliaeetus vocifemides. Proc. VIII Pan-A&. Om. Congr. 192-196.

Zarasoa. 1995a. Etudes socio-Cconomiques des zones humides en vue d’etablir un plan de developpement rural durable et conservation des especes en danger ou menactes d’extinction. In: Watson, R.T. (ed.). Madagascar Project, Wetlands Conservation Project, Progress Report 11, 1993 and 1994. Second Edition: 133- 146. Boise, Idaho: The Peregrine Fund.

Zarasoa, 1995b. Rapport d’etude botanique dans la forCt de Tsimembo (du 15 Mai au 30 Juillet 1994). In: Watson R.T. (ed.). Madagascar Project, Wetlands Conservation Project, Progress Report 11, 1993 and 1994. Second Edition: 147-158. Boise, Idaho: The Peregrine Fund.

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