TUNA FISHING ANALYSIS IN THE SOUTH AND SOUTHEAST OFF BRAZIL FROM 1971 TO 2001

Transcripción

1 SCRS/24/149 Col. Vol. Sci. Pap. ICCAT, 58(5): (25) TUNA FISHING ANALYSIS IN THE SOUTH AND SOUTHEAST OFF BRAZIL FROM 71 TO 21 Marilena Anuska-Pereira 1 ; Alberto F. de Amorim 2 ; Carlos A. Arfelli 2 SUMMARY The goal of the present study is a bibliographic revision of longliner fisheries off south and southeast Brazil. The yield, effort and CPUE data of the main species, like tuna, shark and swordfish, from Santos longliner catches in the period, are also included. Some people were interviewed, using the human memory in order to complement the information related to different results of this analysis. The importance of the Fishing Terminal, and its history, shows the great value of "Baixada Santista" for the tuna fisheries in the studied region, as well as the fisheries in a general way. In the studied period, comprising 3 years, the analysis was done by decades. In the 7s the tuna yield was the highest, comprising three main species: yellowfin tuna (Thunnus albacares), albacore (Thunnus alalunga) and bigeye tuna (Thunnus obesus). It has decreased dramatically in the following decades. In those years there was an advance in the fishery strategy, including the choice of better fishing areas and the use of more sophisticated equipment. All these changes stimulated the exportation of these species. In the 8s the shark yield was the highest, specially the blue shark (Prionace glauca). It was followed by new ways of commercialization and a raise in the commercial value of the fins. In the 9s, and also in 2 and 21, the swordfish (Xiphias gladius) was the most important species in the longliner fisheries, followed by blue shark. The increasing swordfish exportation, contributed to this high yield. It can be also considered the highest yield in the studied period of 3 years, and therefore the most important. As the mentioned species are widely spread all over the Atlantic Ocean, and are caught in different areas by many countries, it is believed that this historical analysis for the period of 3 years will contribute to the conservation of these species in the ocean. RÉSUMÉ La présente étude a pour objet de réaliser une révision bibliographique des pêcheries palangrières opérant au sud et au sud-est du Brésil. Les données de production, d effort et de CPUE des principales espèces, comme les thonidés, les requins et l espadon, capturées par les palangriers de Santos au cours de la période sont également incluses. Certaines personnes ont été interrogées et la mémoire humaine a servi à compléter les informations relatives aux différents résultats de cette analyse. L importance du Terminal de pêche et son histoire témoigne de la grande valeur de «Baixada Santista» pour les pêcheries thonières dans la région étudiée, ainsi que dans les pêcheries en général. Dans la période à l étude, couvrant une durée de 3 ans, l analyse a été effectuée par décennie. Dans les années 7, la production thonière était la plus importante et se composait de trois espèces principales : albacore (Thunnus albacares), germon (Thunnus alalunga) et thon obèse (Thunnus obesus). Celle-ci a chuté spectaculairement lors des décennies suivantes. Au cours de ces années, les stratégies de pêche ont évolué, la sélection des zones de pêche s est améliorée et des équipement plus sophistiqués ont été utilisés. Tous ces changements ont stimulé l exportation de ces espèces. Dans les années 8, la production d espadon était à son apogée notamment celle du requin peau bleue (Prionace glauca). De nouveaux canaux de commercialisation sont apparus et la valeur commerciale des ailerons a augmenté. Dans les années 9 et également en 2 et 21, l espadon (Xiphias gladius) constituait l espèce la plus importante dans les pêcheries palangrières, suivie par le requin peau bleue. La hausse des exportations d espadon a contribué à cette forte production. Elle peut également être considérée comme la plus forte production enregistrée dans la période de 3 ans à l étude, et par conséquent la plus importante. Comme les espèces mentionnées sont largement réparties dans tout l océan Atlantique, et sont capturées 1 UNIMONTE, Part of Master Science, Santos, SP, Brasil anuska.m@uol.com.br 2 Instituto de Pesca, Av. Bartolomeu de Gusmão, 2 Santos, SP, , Brasil crisamorim@uol.com.br, arfelli@pesca.sp.gov.br 1715

2 dans différentes zones par de nombreux pays, on croit savoir que cette analyse historique pour la période de 3 ans contribuera à la conservation de ces espèces dans l océan. RESUMEN El objetivo de este estudio es realizar una revisión bibliográfica de las pesquerías de palangre en las aguas al Sur y Sureste de Brasil. También se incluyen datos de producción, esfuerzo y CPUE de las principales especies, como túnidos, tiburones y pez espada, de las capturas de los palangreros de Santos en el periodo Se entrevistó a algunas personas, utilizando la memoria humana para complementar la información relacionada con los diversos resultados de este análisis. La importancia de la Terminal de pesca, y su historia, muestra el gran valor de "Baixada Santista" para las pesquerías de túnidos en la región estudiada, así como para las pesquerías en términos generales. En el periodo estudiado, que comprende 3 años, se realizó el análisis por décadas. En los setenta se produjo la máxima producción de túnidos, incluidas las tres especies principales, rabil (Thunnus albacares), atún blanco (Thunnus alalunga) y patudo (Thunnus obesus). En las siguientes décadas esta producción experimentó un drástico descenso. En esos años, se produjeron avances en la estrategia pesquera, lo que incluye la elección de mejores caladeros y la utilización de equipos más sofisticados. Estos cambios estimularon la exportación de estas especies. En los ochenta se obtuvo la producción más alta de tiburones; sobre todo de tintorera (Prionace glauca). A esto le siguió el surgimiento de nuevas formas de comercialización y el incremento del valor comercial de las aletas. En los noventa, y también en 2 y 21, el pez espada (Xiphias gladius) fue la especie más importante en las pesquerías de palangre, seguido por la tintorera. La creciente exportación de pez espada contribuyó a este alto nivel de producción. También puede considerarse el nivel de producción más elevado para todo el período de 3 años estudiado y, por tanto, el más importante. Dado que las especies mencionadas presentan una amplia distribución en el océano Atlántico y son capturadas en diferentes zonas por varios países, posiblemente este análisis histórico del período de 3 años contribuya a la conservación de estas especies en el océano. KEYWORDS Longline fishery, CPUE, Yield, Yellowfin tuna, Thunnus albacares, Albacore, Thunnus alalunga, Bigeye tuna, Thunnus obesus, Blue shark, Prionace glauca, Swordfish, Xiphias gladius 1. Introduction Tuna fisheries in Brazil started in 56 in Recife City, Pernambuco State, with a fleet of a Japanese company. This fleet of 12 boats had excellent results in 59, and in 61 it increased to 15 (Paiva, 61, Amorim 76). It operated until 64, and stopped for economic reasons, resuming in 68 (Paiva and Le Gall 75) and stopping again in 71 (Paiva 75). So the tuna fishing showed a decline in Brazil until 68. In the meanwhile, boats from other countries started fishing tuna in our country, attracted by the abundance, and unloading in neighboring countries for exportation (Amorim 76). The same Japanese company has also settled another base in Santos city, São Paulo State, operating in the south and southeast off Brazil from 58 to 61 (Moraes 62; Morais 63). In 65/66 the first national longline fleet started fishing, settled in Santos, and it is operating up to now. Another national company, settled in Rio Grande City, Rio Grande do Sul State, was opened in 77, with the leasing of three Japanese boats, and only in 82 a national boat started operating. Two boats operated from 82 to 92. The leased boats (Japanese, Korean and Taiwanese) stopped fishing in 95, and nowadays this activity is discontinued in Rio Grande. In Natal city, Rio Grande do Norte State, the national fleet started operating with small boats in 83 (Antero-Silva et al. 94), and it is working until now. In Belém city, Pará State, a leased Taiwanese fleet has operated since 92 (Amorim, Arfelli, Bacilieri, 22). The same fleet started operating in Cabedelo city, Paraíba State, in 95. This city showed the greatest increase in fishing activities of the northeast. In 97 this fleet also received leased Portuguese and Spanish boats, being active up to now (Weidner and Arocha 99). In Cabedelo, the yield of longliners increased from 3, t in 99 to 1, t in

3 The national fleet started operating in 65/66 with two boats (Arfelli and Amorim 88). This number increased up to 2 boats in 98, decreasing to 14 from 2 to 21. In 21 these tuna boats ranged from 26 to 149 (gross tons) and measured from 16 to 33 m. In 94 this fleet starts changing the traditional Japanese longline by a longline known as monofilament. This new equipment, similar to the one used by American fleet, is made of nylon monofilament and uses light attractors targeting swordfish (Arfelli 96). According to Amorim and Arfelli (21), by the end of 96 most of the boats had already changed to monofilament. This paper compiles and analyses the historical series of statistical data on fisheries from tuna boats settled in Santos city, São Paulo State, Brazil, from 71 to 21. The studied fishing area is comprised between 17 to 35 S and 27 to 52 W (Arfelli 96). 2. Material and methods The yield data, in tons, by species or groups of species caught from 71 to 21, the effort (number of hooks cast) and the fishing area analyzed in this paper came from the Instituto de Pesca. The yield data were obtained from fishing companies (sales records) and the effort and area from logbooks of the tuna boats. The yield, in individual dressed weight, recorded by month and year of the studied period was converted in live weight. The methodology used in the data analysis is based on Santos (78), Amorim and Arfelli (84) and Amorim (92). 3. Results and discussion The figures from 1 to 8 show the yield, effort and CPUE of tunas, sharks and alike caught from 71 to 21 by tuna boats settled in Santos. In Figure 1, it is observed a similarity between the total annual yield of tuna boats based in Santos, including all the species, and its fishing effort from 71 to 99, both showing an increasing trend. The yield ranged from t in 73 to 3,597.5 t in 94 and the effort from 432 thousand hooks in 72 to 3 million 886 thousand hooks in 93. The increase in yield and effort was due to the increasing number of boats. In the Figure 2, that shows the percentage of sharks and of tuna and alike, it is possible to see a great fluctuation. In the 7s that tuna and alike represented 8%, decreasing to 42% (93) and increasing again up to 72% (97). Consequently the sharks ranged to the opposite side. In the beginning of the period (71 to 77), they represented just about 17%, gradually increasing to 58% (93), decreasing to 28% (97) and increasing again to 56% (21). The increasing percentage of sharks is mainly due to the decline of three species of tunas and consequently a increasing the demand for sharks (Amorim 92). The same change in the relative abundance of tunas and sharks also happened in the northeast of Brazil from 83 to 88 (Hazin et al. 9). After the decrease of tunas, the fishing companies wanted to keep their profits, so they changed their strategy of selling sharks, and then their prices went up. With a higher value of the shark meat in the market, the tuna boats activity started expanding again (Amorim, 92). In Figure 3, yield of tunas, sharks, swordfish and other fishes is shown. Tunas varied from 276 t in 72 to 1,9 t in 79, gradually declining to 86 t in 21. The sharks, initially with 113 t (72) increased to 1,892 t (94), decreasing to 813 t in 21. The swordfish, with a low yield in the beginning of the period, 11 t in 72, showed a peak in 8. After 94 there was a great increase in the yield of this species, reaching 1,394 t in 95. Their catch was 441 t in 21. Other fishes presented small variations of 21 t in 73 to 181 t in 92. In Figure 3, it is observed that in the 7s tunas represent most of the production. This increasing trend is due to an improvement in the fishing strategy, choosing a better area and more sophisticated equipments. So, with the help of a good radio communication among the boats, informing the best fishing areas to all fishermen, the traditional fishing areas were abandoned and people started fishing in new and more productive ones. For this reason there was an increase of productivity followed by the exportation of the fish. 1717

4 This exportation called the attention of international companies that comes fishing in international waters off southern and southeastern Brazil. Consequently it was observed a decrease in the production of national boats that had little autonomy and were limited to the traditional area (Amorim 76; Amorim and Arfelli, 84; Amorim 92). The swordfish has been caught since the beginning of the fisheries (Figure 3). The peak registered in 8, resulted from changes in the kind of bait used, depth, area and mainly the schedule. This increase was discontinued because swordfish hooked start being intensively attacked by the dolphin orca, Orsinus orca. Then the fishermen preferred to aim their capture to the traditional fish, and the catch of swordfish decreased (Amorim and Arfelli 84). In 94 the capture of this fish increased again and is still high up to now, with the use of new kind of longline, being now targeted species (Arfelli 96). In Figure 4, it is observed the production of three main species of tuna (yellowfin, albacore and bigeye), swordfish and blue shark. In 79, the production of yellowfin reached a peak (695 t), in 98 the same happened with albacore, reaching 386 t. Bigeye presented an instable production during the period: 28 t in 72; 7 t in 74; 25 t in 89; 7 t in 97. The species blackfin tuna (T. atlanticus) is not represented in the figure due to its extremely low production. In the first decade the tunas were the targets of this fishery, specially the yellowfin with an average of 348 t. Although swordfish wasn t the target, it presented an average of 256 t. In the second decade, blue shark had the highest average of 497 t, followed by swordfish with 486 t. In the last decade (including 2 and 21), swordfish presented the highest average (1,37 t), followed by blue shark with 83 t. For the studied period, swordfish is in first place with an average of 6 t, followed by blue shark with 487 t. In Figure 5, the yield of five groups of sharks, comprising many species is presented. The average yield of mako, from 71 to 21 was around 82 t, ranging from 29 t in 71 to 168 t in 91. The blue shark, in the beginning of the period (71 74), presented an average yield of 6 t, because the species was rejected due to the low price. At that time, the fishermen worried just about the use of the fins and maintenance of the hook. From 75 on the boats increased the capture of blue shark, bringing initially the specimens caught in the last 1 days of the trip, for being fresher. Gradually they started bringing the blue shark caught, increasing to 58 t in 75. In 84 the yield reached around 774 t. The highest yield was 1,244 t in 94. After this period, there was a decline and in 21 the yield was 65 t. In the studied period the average of blue shark catch was 487 t. Hammerhead, especially the two main species Sphyrna lewini and S. zigaena, presented an average of 74 t from 71 to 21. The highest and lowest yield was respectively 27 t in 9 and 7 t in 72. In the studied period thresher presented an average of 34 t, with the highest yield of 85 t in 9 and 1 t in 71. Other sharks, clustered, presented an average of 145 t, with the lowest yield around 5 t and the highest of 39 t in 94. With the increase of the blue shark meat and other sharks, the fishing companies kept their profit, due to the increase in yield. Figure 6 presents the catch per unit of effort of the tunas, which showed a high decline trend in the studied period. The CPUE of yellowfin decreased from 538 in 72 to 16 (kg/thousand hooks) in 21. For bigeye the CPUE was 272 in 74 to 16 in 21. Figure 7 shows CPUE of blue shark from 71-21, which presented an increasing trend. The CPUE changed from 5 in 72 to 528 in 96 and, in 21 was 342. Blue shark was one of the main species caught, keeping the profit of this activity from the 8s on. The CPUE of swordfish (Figure 8) presented high fluctuations, with an increasing trend. It was 8 (kg/thousand hooks) in 71, 956 in 8 and 1,34 in 96. Swordfish is supposed to be the main support of the tuna fishery, although it had presented a low value in the beginning of the studied period. Even with a considerable fishing effort over this species in the mentioned period, the CPUE tendency is following the effort. In the 7s the tuna companies form Santos city had great difficulty in the commercialization of their product. Practically all the fish was sold to the Japanese and Spanish colonies, and later the Asian, Arabian and also from other European countries. At this time just the shark fins had commercial value. Up to the end of that decade, some swordfish and sharks were donated in order to stimulate the consumption. Just the tuna meat had a good acceptance in the market. 1718

5 In the 8s, the seasonal fluctuation of the species and the great competitively of foreign boats, the production of tunas started to decrease. The bigeye, main specie used for sashimi, with a high price in the market, started to disappear. The yellowfin, largely used in the cannery industry, also decreased a lot. Even the albacore, with lower commercial value, known as Brazilian sashimi, also decreased. Sharks attained more acceptances in the market, after some changes in the commercialization. Instead of being commercialized in natura, they were sold frozen or dry cured. In the 9s, the prices of tunas increased, maybe due to their scarcity. Sharks, despite the fluctuations in the catches, kept a good position in the market, due to the new ways of commercialization. Blue shark is one of the most important products in the fisheries in the south and southeast regions. Their fins are exported and considered the best, reaching the price of 8 dollars per kg. The swordfish became the most important product in the exporting market, and expensive and scarce in the domestic market. 4. Conclusion The tuna boat fleet settled in Santos unloads their product in the Fishing Terminal in Santos City, Sao Paulo State, because their main product, swordfish, is almost all exported through the International Airport of Guarulhos, in Sao Paulo State also. The production of swordfish expanded at the same time that the exportation increased, leaving very little of this product in the domestic market. The sharks, with new ways of conservation and packaging, conquered a better place in the market, also with the raise of the fin prices. The production of tunas declined, but the tuna fishing maintains the same level due to swordfish and blue shark. References AMORIM, A. F. 76. O que teria acontecido às pescarias de atuns? e A pesca de atum no sul-sudeste do Brasil. Pesca em Revista, Santos-SP (7): AMORIM, A. 92. Estudo da biologia da pesca e reprodução do cação-azul, Prionace glauca L. 1758, capturado no sudeste e sul do Brasil. 25f. Tese de doutorado. Instituto de Biociências, UNESP, Campus de Rio Claro. São Paulo. AMORIM, A. and C.A Arfelli. 84. Estudo biológico-pesqueiro do espadarte, Xiphias gladius L. 1758, no Sudeste e Sul do Brasil, (71 a 81). B. Inst. Pesca, São Paulo 11 (único): AMORIM, A. and C.A. Arfelli. 21. Analysis of Santos (São Paulo), fleet from Southern Brazil (71-99). Col. Vol. Sci. Pap. ICCAT, Madrid 53: AMORIM, A, C.A. Arfelli, and S. Bacilieri. 22. Shark data from Santos longliners fishery Southern Brazil. Col. Vol. Sci. Pap. ICCAT, Madrid 54(4): ANTERO-SILVA, J.N., A.F. Amorim, R.P.T. Lessa, F.H.V. Hazin, C.A. Arfelli. 94. White marlin (Tetrapturnus albidus) fisheries off Brazilian coast from national and leased longliners fleet. Report of the Second ICCAT Billfish Workshop, Col. Vol. Sci. Pap. ICCAT, Madrid 41: ARFELLI, C.A. 96. Estudo da Pesca e Aspectos da dinâmica populacional de espadarte, Xiphias gladius L. 1758, no Atlântico sul. 175p. Tese de Doutorado em Ciências Biológicas, Área de Zoologia. Instituto de Biociências, UNESP, Campus de Rio Claro. São Paulo. ARFELLI, C.A. and A.F. Amorim. 88. Description of the Brazilian swordfish fishery in Santos. Col. Vol. Sci. Pap. ICCAT, Madrid 27: HAZIN, F.H.V., A.A. Couto, K. Kihara, K. Otsuka, M. Ishino. 9. Distribution and abundance of pelagic sharks in the South-western equatorial Atlantic. Journal of the Tokyo University of Fisheries (7791): MORAES, M. N. 62. Development of tuna fishery of Brazil and preliminary analysis of the first three years data. Arq. Est. Biol. Mar. Univ. Ceará, Fortaleza 2(2):

6 MORAIS, S. B. 63. Uma pescaria do atuneiro Kaiko Maru 12. B. Est. Pesca, Recife 3 (5): PAIVA, M.P. 61. Sobre a pesca dos atuns e afins nas áreas em exploração no Atlântico tropical. Arq. Est. Biol. Mar. Univ. Ceará, Fortaleza 1(1): 1-2. PAIVA, M.P. 75. Datos recientes sobre la investigacion y la pesqueria de túnidos y especies afines en Brasil. In: COMISION INTERNACIONAL PARA LA CONSERVACIÓN DEL ATUN ATLANTICO. Informe... (74-75) Madrid (1): PAIVA, M.P., J.Y. Le Gall. 75. Catches of tunas and tuna like fishes in the longline fishery areas off the coast of Brazil. Arq. Cien. Mar. 15 (1): SANTOS, E.P. 78. Dinâmica de Populações Aplicada à Pesca e Piscicultura. São Paulo: HUCITEC, Ed. Da Universidade de São Paulo, 129 p. WEIDNER, D.M., F. Arocha 99. South America: Atlantic, Part A., Section 2 (segment B) in Latin America, WORLD SWORDFISH FISHERIES : An Analysis of Swordfish Fisheries, Market Trends, and Trade Patterns, IV (NMFS: Silver Spring, Maryland, February, 99). 172

7 t Yield and effort of longliner Effort Yield Figure 1. Yield (t) and fishing effort (thousands/hooks) of longliners settled in Santos (71-1). Percentage of tuna and others and shark caught by longliner % Tuna and other Shark Figure 2. Percentage of yield of sharks and tuna and alike from Santos longliners. Yield of tuna, shark, swordfish and others 2 Tuna Shark Swordfish Other 15 t Figure 3. Yield of tunas, sharks, swordfish and other fishes from Santos longliners. 1721

8 t Yield of the main species caught by longliner Yellowfin Albacore Bigeye Swordfish Blue shark Figure 4. Yield of tunas, swordfish and blue shark from longliners settled in Santos. Yield of sharks t Mako Blue shark Hammerhead Thresher Other Figure 5. Yield of mako, blue, hammerhead, thresher and others sharks from Santos longliners. Tunas CPUE 6 5 Yellowfin Bigeye Albacore Kg/1 hooks Figure 6. Catch per unit of effort from 71 to 21 of Santos longliners. 1722

9 Blue shark CPUE Kg/1 hooks Blue shark Figure 7. Catch per unit of effort (kg/thousand hooks) of blue shark by Santos longliners. Swordfish CPUE Kg/1 hooks Swodfish Figure 8. Catch per unit of effort of swordfish (kg/thousand hooks), from 71-21, by Santos longliners. 1723