Bycatch in 36 and 40 mm PA Turkish twin rigged beam trawl codends

Bok T. D., Gokturk D., Kahraman A. E.

AFRICAN JOURNAL OF BIOTECHNOLOGY, cilt.10, sa.37, ss.7294-7302, 2011 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 10 Sayı: 37
  • Basım Tarihi: 2011
  • Dergi Adı: AFRICAN JOURNAL OF BIOTECHNOLOGY
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Aquatic Science & Fisheries Abstracts (ASFA), Biotechnology Research Abstracts, CAB Abstracts, Pollution Abstracts, Veterinary Science Database
  • Sayfa Sayıları: ss.7294-7302
  • Anahtar Kelimeler: Beam trawl, rose shrimp, Parapenaeus longirostris, bycatch, discards, minimum landing size, Sea of Marmara, Turkey, HAKE MERLUCCIUS-MERLUCCIUS, SQUARE-MESH CODENDS, SELECTIVITY EXPERIMENTS, DIAMOND-MESH, BY-CATCH, FISHERY, DISCARDS, REDUCE, SOLE, PE
  • İstanbul Üniversitesi Adresli: Evet

Özet

The Turkish twin rigged beam trawl which has two identical nets rigged side by side on the same beam targets mainly the Parapenaeus longirostris, although some bycatch fish species have also become target species. Thus, landings of the shrimp beam trawling fleet also include some commercially valuable fishes. Our study focused on the bycatch commercial species which are caught by the beam trawl fishery with nominal mesh sizes 36 and 40 mm PA (diamond) codend in the Sea of Marmara (Turkey) and also on the minimum landing size (MLS) established for Merluccius merluccius, Merlangius merlangus euxinus, Mullus surmuletus, Trachurus trachurus and Pomatomus saltatrix. Since there was no MLS value for Spicara smaris, the length at first maturity (LFM) was used for this species. Experiments were carried out onboard the commercial beam trawler. In 20 hauls, the average codend catch weight was 63.12 kg for 36 mm PA and 66.51 kg for 40 mm PA. On the other hand, for 36 mm PA, 83.5% of M. merluccius, 74.3% of M. merlangus euxinus, 29.7% of T. trachurus, 10.8% of P. saltatrix and 8.6% of M. surmuletus were below the MLS. For 40 mm PA, 88.9% of M. merlangus euxinus, 87.7% of M. merluccius, 42.5% of T. trachurus, 7.2% of P. saltatrix and 6.7% of M. surmuletus were below MLS. In addition, 7.5% of S. smaris were below length at first maturity (LFM) for 36 PA codends.