CELALETTİN AYDIN, M.Hakan KAYKAÇ, Adnan TOKAÇ

Türkiye geleneksel trol balıkçılığına ikili ızgara sistemlerinin uygulanması

Bu çalışmada, trol ağlarında ikili ızgara sistemleri kullanarak ticari olmayan tür oranının azaltılması amaçlanmıştır. Denemeler geleneksel yapıdaki dip trolü le Ocak-Mart 2003 tarihleri arasında izmir Körfezinde yürütülmüştür. Çalışmada, iki ızgaralı iki farklı sistem kullanılmıştır. İlk sistemde, 150 ve 17 mm çubuk aralığına sahip her iki ızgara çekim yönünde 45° ile donatılmıştır. İkinci sistemde, 150 ve 15 mm çubuk aralığına sahip ızgaralar çekim yönünde sırasıyla 135° ve 45° ile donatılmıştır. Krom nikel malzemeden yapılan ızgaralar 5 m uzunluğundaki uzatma parçasına donatılmıştır. Uzatma parçasında ilk ızgaranın donatıldığı bölgede büyük boyuttaki ticari olmayan türlerin ve istenmeyen cisimlerin serbest bırakılması için açıklık vardır (birinci sistemde üst, ikinci sistemde alt panelde). Izgaradan kaçan balıkların yakalanması için poliamid 17 mm tam göz boyundaki torbalar kullanılmıştır. Farklı torbalarda yakalanan balıklar ticari ye ticari olmayan olarak ayrılmış ve toplam sayı ve ağırlıkları alınmıştır. Barbunya birinci ve ikinci sistemde sırasıyla yüzde 50.1 ve 43.14 ile en çok yakalanan tür olmuştur. Bu tür çalışmalarda, sualtı kameraları ve ızgara sensörierinin kullanımı ızgara seçiciliğinin geliştirilmesi için yararlı olacağı oldukça açıktır.

Anahtar Kelimeler:

balık avlama ekipmanı, Türkiye, tuzak ağlar, av kompozisyonu (balık), balık avlama

Application of double grid systems in Turkish traditional trawl fisheries

In this study, it was aimed to reduce of noncommercial species using double sorting grid in trawl net. Experiments were carried out between January and March 2003 with traditional bottom trawl in the Izmir Bay. Two different systems with two grids were used in the study. In the first system both grids were rigged at 45° angle through towing direction with 150 and 17 mm bar spacing, respectively. In the second system, first grid . was 135° angle, second was 45° angle rigged with 150 and 15 mm bar spacing, respectively. Sorting grids made of chrome nickel were rigged to the 5 m in length extension piece. There were hole (upper hole in first system, bottom hole in second system) in the extension piece which connected to the first grids in order to release big size noncommercial species and obstructing material. To catch of fish escaping from sorting grids were used polyamide codends have 17 mm mesh size. Caught fishes separated to the commercial and non commercial species according to the different codends and their total number and weight were measured. Red mullet (Mullus barbatus) was dominated fish species both first and second systems with 50.5 and 43.1 %, respectively. It is clear that using underwater cameras and grid sensors in this type studies will be very useful to improve grid selectivity.

Keywords:

fishing gear, Turkey, nets, catch composition, fishing,

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Alleverson, D. L, M. H. Freeberg, S. A. Murawski, and J. G. Pope. 1994. A Global Assesment of Fisheries Bycatchs and Discards, FAO Fisheries Technical Paper No:339, Rome, 233p.

Aydın, C, Z. Tosunoğlu, and A. Tokaç. 2001. Improvement of bottom trawl nets by using grid systems (in Turkish). E.Ü. Journal of Fisheries and Aquatic Science. Vol. 18, Issue (1-2):91-101.

Aydın, C. 2004. Aplication of Sorting Grid Systems to Exclude By-catch and Discard Species in Trawl Fisheries (In Turkish).Ph.D Thesis. Instutute of Naturel and Applied Science, Bornova. İzmir. Turkey. 184p.

Broadhurst, M.K., 2000. Modifications to reduce bycatch in prawn trawls: A review and framework for development, Reviews in Fish Biology and Fisheries., 10:27-60.

Caudillo, J.M.G., MAC. Mata and A.B. Ramiroz. 2000. Performance of bycatch reduction device in the shrimp fishery of the Gulf of California, Mexico, Biological Conservation, 92:199-205.

Cook, R. 2001. The Magnitude and impact of Bycatch Mortality by Fishing Gear, Reykjavik Conference on Responsible Fisheries in the Marine Ecosystem, Reykjavik, Iceland, 18p.

Coutinholl, R. and G.V.S. Quteria. 1999, The Problem of discard in fisheries, Final Report, No. EP/IV/B/STOA/98/170/ Portugal, 78p.

Isaksen, B., J.W. Valdemarsen, R.B. Larsen, and L. Karisen, 1992, Reduction of fish by catch in shrimp trawl using a rigid separator grid in the aft belly, Fisheries Research, 13:335-352.

Kendall, D. 1990. Shrimp retention characteristics of the Morrison Soft Ted: a selective webbing exclusion panel inserted in a shrimp trawl net, Fisheries Research, 9:13-21.

Larsen, R.B., and B. Isaksen. 1993. Size selectivity of sorting grids in bottom trawls Atlantic cod {Gadus morhua) and haddock (Melanogrommus aeglefinus) ICES Mar. Sci., Symp., 196:178-182.

Larsen, R.B. 1996. Experiments with a new, large type of fish/shimp separator grid and comparasions with the standard Nordmore grid. ICES FTFB W.G. Meeting, Woods Hole, USA, 61 p.

Lossius, L.L. 1997. Size Selection of Northern Shrimp {Pandalis borealis) by Metal Sorting Grids in the Shimp Trawls. Cand. Scient. Thesis in the Fisheries Biology. Departman of Fisheries and Marine Biology Universirty of Bergen, 112p.

Madsen, N. and K. E. Hansen. 2001. Danish experiments with a grid system tested in the North Sea Shrimp Fishery, Fisheries Research, 52:203-216.

Main, J. and G.I. Sangster. 1985. Trawling experiments with a two level net to minimize the undersized gadoid by-catch in a nephrops fishery, Fisheries Research, 3:131-145

Main, J. and G.I. Sangster. 1990. An Assessment Of The Scale Damage To And Survival Rates Of Young Gadoid Fish Escaping From The Cod-End Of A Demersal Trawl, Scot., Fish., Research., Report No: 46,28p.

Metin, C, Z. Tosunoğlu, A. Tokaç, A.. Lök, C. Aydın, and H. Kaykaç. 2000. Seasonal variations of demersal fish composition in Gülbahçe Bay (İzmir Bay), Turk J.Zool., 24:437446.

Petovello, A.D. 1999. By-catch in the Patagonian red shrimp (Pleoticus muelleri) fishery, Mar. Freshwater Res., 50:123-127.

Riedel, R., and J. DeAlteris. 1995. Factors affecting hydrodynamic performance of the Nordmore grate system: a by-catch reduction device used in the Gulf of Maine shrimp fishery, Fisheries Research 24:181- 198.

Suuronen, P., E. Lehtonen, V. Tschernij, and A.. Orrensalo. 1993. Survival of baltic herring (Clupea harengus L.) escaping from a trawl codend and through a rigid sorting grid. ICES Statutory Meeting CM. 1993/B:1.

Thomsen, B. 1993. Selective flatfish trawling, ICES Mar, Sci., Symp., 196:161-164.

Tokaç, A., H. Ozbiigin, and T. Tosunoğiu. 2004. Effect of PA and PE material on codend selectivity in Turkish bottom trawl, Fisheries Research, 67;317-327.

Tokai, T., S. Omoto, R. Sato, and K. Matuda. 1995. A methods of determining selectivity curve of separator grid. Fisheries Research 27:51-60.

Tosunoğiu, Z. 1998. Structural Modification to Improve Cod-End Selectivitiy at The Bottom Trawl Nets Used in Turkish Seas (In Turkish).Ph.D. Thesis. Instutute of Naturel and Applied Science, Bornova, Izmir. Turkey. 121 p.

Valdemarsen, J.W. 1996. A Review Of Norvegian Research With Grid Sorting Devices İn Towed Fishing Gears ICES Study Group On Grid (Grate) Sorting Systems in Trawls, Beam Trawl and Seine Nets. Woods Hole, Massachussets, USA, 61 p.

Watson, J.W., I.K. Workman, D. Foster, C. Taylor, A Shah, J. Barbour, and D. Hataway. 1993. Status Report On The Development Of Gear Modifications To Reduce Finfish By-Catch in Shrimp Trawls in The Southestem United States, 1990-1992, NMFS, Pascagula, MS, 130p.

Wileman, D.A., R.S.T. Ferro, R. Fonteyne, and R.B. Millar (eds.). 1996. Manual of Methods of Measuring the Selectivity of Towed Fishing Gears. ICES Cooperative Research Report, No. 215, Copenhagen.