THE ALBACORE FISHERY IN TURKEY

Transcription

1 SCRS/2010/073 Collect. Vol. Sci. Pap. ICCAT, 66(5): (2011) THE ALBACORE FISHERY IN TURKEY Tevfik Ceyhan 1, Okan Akyol, F. Saadet Karakulak SUMMARY The albacore fishery, which started in 2004, is a new activity in Turkey. The albacore fleet is comprised of about 40 vessels ranged from 10 to 34 m LOA. The engine power of these vessels varies between 34 and 1520 HP. The albacore gillnet was made of 210d/21 no, multifilament polyamide (PA) 170 mm mesh size netting, and mesh deep. Fishermen have made some modifications in their nets and put weights on the lower parts of the nets in order to get out of scope of driftnet definition in Notification 2/1 Regulating Commercial Fishing. Albacore (Thunnus alalunga) and swordfish (Xiphias gladius) are target species in this fishery. Furthermore, common dolphinfish (Coryphaena hippurus), bluefin tuna (Thunnus thynnus), ocean sunfish (Mola mola), bullet tuna (Auxis rochei), litlle tunny (Euthynnus alletteratus) and Mediterranean spearfish (Tetrapturus belone) are being caught as by-catch. RÉSUMÉ La pêcherie de germon, qui a démarré en 2004, est une nouvelle activité en Turquie. La flottille de germon comprend environ 40 navires mesurant entre 10 et 34 m de longueur hors-tout. La puissance motrice de ces navires varie entre 34 et CV. Le filet maillant pour le germon était constitué de 210d/21 no, de multifilament polyamide (PA) d un maillage de 170 mm, doté d une profondeur de Les pêcheurs ont fait quelques modifications à leurs filets et ont ajouté des poids dans les sections inférieures des filets afin d échapper à la définition de filet dérivant énoncée dans la Notification 2/1 réglementant la pêche commerciale. Le germon (Thunnus alalunga) et l espadon (Xiphias gladius) sont les espèces-cibles de cette pêcherie. En outre, la coryphène commune (Coryphaena hippurus), le thon rouge (Thunnus thynnus), le poisson lune (Mola mola), le bonitou (Auxis rochei), la thonine commune (Euthynnus alletteratus) et le marlin de la Méditerranée (Tetrapturus belone) sont capturés en tant qu espèces accessoires. RESUMEN La pesquería de atún blanco, que se inició en 2004, es una actividad nueva en Turquía. La flota de atún blanco se compone de aproximadamente 40 barcos que oscilan entre 10 y 34 m de LOA. La potencia de motor de estos barcos varía entre 34 y 1520 cv. La red de enmalle dirigida al atún blanco está hecha de 210d/21 no, trasmallo de multifilamento de poliamida (PA) de 170 mm, y tiene una profundidad de malla de Los pescadores hicieron algunas modificaciones en sus redes y pusieron pesos en las partes inferiores de las redes con el fin de que no se incluyeran en la definición de redes de enmalle a la deriva incluida en la Notificación 2/1 que regula la pesca comercial. Las especies objetivo de esta pesquería son el atún blanco (Thunnus alalunga) y el pez espada (Xiphias gladius). Además, se capturan como captura fortuita dorado (Coryphaena hippurus), atún rojo (Thunnus thynnus), pez luna (Mola mola), melvera (Auxis rochei), bacoreta (Euthynnus alletteratus) y marlín del Mediterráneo (Tetrapturus belone). KEYWORDS Albacore, Thunnus alalunga, gillnetting, Mediterranean 1 Ege University Faculty of Fisheries, Bornova, Izmir, Turkey. tevfik.ceyhan@ege.edu.tr 1867

2 1. Introduction Albacore (Thunnus alalunga) is highly migratory species and distributed in tropical and temperate waters of all oceans including the Mediterranean Sea, extending north to 45 to 50 N and south to 30 to 40 S but not at the surface between l0 N and 10 S (Collete and Nauen, 1983). ICCAT (1996) has separated the albacore stocks as North, South Atlantic and Mediterranean for management purposes. Megalafonou (2000) stated that The Italian and Greek fisheries for albacore were the most important in the area and produce the bulk of the catches. In Greece, fishing took place mainly in the northern Aegean Sea from the end of August until November with long lines and troll lines. In Italy, albacore fishing was practised in the Ionian, southern Adriatic and Tyrrhenian Sea with longlines and drift nets from September to December. In the area of the Tyrrhenian Sea albacore fishing was also conducted during April through to August. In Turkey, targeted albacore fishery started in In the beginning of this fishery, one boat caught albacore by gillnet as target species. After joining the 8-10 boats in one year later, albacore fishery has tend to develop (Y. Bostan pers. comm.). Total annual albacore catch in Turkey was 208 mt in 2008 (FAO, 2000). The maximal amount in the world was recorded as mt in 1999, and declined to about mt in 2008 (FAO, 2000). The maximum albacore catch in Turkey was realized as 852 mt in Turkish albacore fishery reached approximately to 13% of the Mediterranean annual yield in The unique study on albacore fishery in Turkey was published by Karakulak et al. (2007). The authors explained that the albacore pelagic gillnet fishery was carried out for the first time in 2004 in national and international waters in the Gulf of Antalya. The depth at the fishing grounds ranged from 150 to 2300 m. These drift-nets were approximately 2 km in length and 150 meshes in depth with a mm mesh. Illuminated buoys were attached to each side of the net. Nets were set at sunset and retrieved at sunrise. The main objectives of this study were to describe the current status of albacore fishery and technical characteristics of the fleet and fishing gears. 2. Materials and methods Data on number of fishing vessels, the corresponding catch, non-target catches, fishing gear s characteristics and location of the fishing grounds were obtained via personal observations and questionnaires at fishing ports during the surveys in 2009 and Fork length (FL) of albacores was measured on board off the Alanya coast. 3. Results and discussion The albacore fishing has been carried out intensively between 15 May and 15 July in the Gulf of Antalya. The Gazipaşa, Alanya, Manavgat, Antalya and Kaş are main fishing ports for Albacore fisheries. The fisheries have been accomplished at sea ( depth) nautical miles up from Alanya (Figure 1). After decreasing of catch efficiency at the mid of the July, half of the fleet goes to Sığacık Bay in order to catch some swordfish. Approximately 40 vessels join this fishery during between May and July. The number of vessels and the fishing ports are shown in Figure 1. The length of vessels was between m LOA and engine power of these vessels varies between 37 and 1520 hp (Table 1). The numbers of crew on board have been varying between 2 and 11. The consumption of fuel was ranging from 50 to 500 l.day -1 due to staying at sea for 2 or 4 days. Karakulak et al (2007) stated that the albacore fishery was carried out by 18 vessels and these vessels had m LOA and hp engine power. The difference between our results and Karakulak et al. (2007) might be occurred due to increasing of the fleet. The albacore gillnet was made of 210d/21 no, multifilament polyamide (PA) 170 mm stretched mesh size netting, and meshes deep. Hanging ratio (E) was The plastic buoys and sinkers 400 g in weight were attached to the both lines (Figure 2). Despite the fact that, Akyol et al (2008) determined two types gillnet from albacore fishery, the modified gillnet is drawn for the first time. Fishermen have made some modifications 1868

3 in their nets and put weights on the lower parts of nets in order to get out of scope of driftnet definition in Notification 2/1 Regulating Commercial Fishing. In order to using alternative fishing methods such as longlining, Ministry of Agriculture and Rural Affairs (MARA) should provide grant supports to the fishermen. The albacore (Thunnus alalunga) and swordfish (Xiphias gladius) are target species in this fishery. Furthermore, common dolphinfish (Coryphaena hippurus), bluefin tuna (Thunnus thynnus), ocean sunfish (Mola mola), bullet tuna (Auxis rochei), litlle tunny (Euthynnus alletteratus) and Mediterranean spearfish (Tetrapturus belone) are being caught as by-catch. Loggerhead turtle (Caretta caretta) are being caught sometimes, as well. However, fishermen argued that they have set the all loggerhead turtles free as alive. Karakulak et al. (2007) reported that the non-target species were bluefin tuna, swordfish, Atlantic black skipjack, bullet tuna and dolphinfish, and no common dolphin, sperm whales and birds were caught. A total of 155 specimens of albacore were measured. Fork length of albacore ranged from 57 to 94 cm, with nearly one third of the fish (33 %) in the cm range, and the average length was 71.7 ± 0.48 cm (Figure 3). Megalafonou (1990) stated that the fork length of albacore ranged from 54 to 89 cm and means were 68 ± 4.21 cm, 67.6 ± 3.77 cm and 72.6 ±4.56 cm for 1986, 1987 and 1989, respectively. Megalafonou (2000) also reported length of albacore ranged from 57 to 92 cm. Karakulak et al. (2007) reported that the total length of albacore ranged from 64.0 to 94.0 cm (mean length: 75.7±0.4 cm). The mesh deep of different gillnet has been appeared the important problem by the fishermen. They have stated the deeper gillnets affected catch efficiency of the lesser one. However, the lower marketing value of fish is the second problem. Whole fish were only bought by some fish canning factories. Namely, the cost of fish can be determined by these buyers. It can be sold for 1-2 euros/kg. In conclusion, albacore fishery in a certain area is newly activity in Turkey. This fishery is executed by lower fishing effort. Further studies on fishing effort, CPUE, fish biology, by-catch and discard ratios etc. are essential for sustainability. Acknowledgements This study is supported by TUBITAK project no: 108 O 210 and the authors wish to thank to chair and members of the Assoc. of the Fishing for Swordfish and Albacore for their help during the fish measurements and for given the opportunity to work freely onboard. References Akyol, O., Karakulak, F.S., Ceyhan, T., Dede, A. 2008, Driftnets, used in Turkish Seas and the regulations. Journal of Fisheries and Aquatic Science. 25(2): (in Turkish) Collete, B.B., Nauen, C.E. 1983, FAO Species Catalogue. Vol. 2. Scombrids of the World. FAO Fisheries Synopsis. No. 125, 2, 137 Pp. FAO 2000, Fishstat Plus: Universal Software for Fishery Statistical Time Series. Version 2.3. FAO Fisheries Dept., Fishery Information, Data and Statistics Unit. Rome. ICCAT 1996, Report of the Final Meeting of the ICCAT Albacore Research Program. Collect. Vol. Sci. Pap, ICCAT, 43: 395-XX. Karakulak, F.S., Bilgin, B. and Gökoğlu, M. 2007, Albacore (Thunnus alalunga, Bonnaterre, 1788) fishery in Antalya Bay (Levantine Basin). Rapp. Comm. İnt. Mer Medit., 38: 512. Megalofonou, P. 1990, Size distribution, length-weight relationships, age and sex of albacore, Thunnus alalunga Bonn., in the Aegean Sea. Collect. Vol. Sci. Pap. ICCAT, 33: Megalafonou, P., 2000, Age and growth of Mediterranean albacore. Journal of Fish Biology 57,

4 Table 1. Some fleet characteristics of albacore vessels. Mean ±SE n (min.-max.) Σ Boat length (m) ± 1.54 (10 34) Tonnage (GT) ± 10.6 ( ) Engine power (hp) ± 70.7 ( ) Boat age (year) ± 2.7 (2 51) Fuel consumption (l day -1 ) ± 25.6 (50 500) Personnel 5.6 ± (2 11) Figure 1. Distribution of fishing ports and fishing area for albacore (numbered circles indicate the total number of albacore vessels). 1870

5 Figure 2. Modified gillnet for albacore fishery. % FL (cm) Figure 3. Length frequency of albacore in Gulf of Antalya. 1871