Scientia Marina, Vol 74, No 4 (2010)

Survival of fish after escape from a 40 mm stretched diamond mesh trawl codend in the Aegean Sea

Faik Ozan Düzbastilar
Ege University, Centre of Underwater Research and Application , Turkey

Celalettin Aydin
Ege University, Fisheries Faculty , Turkey

Gülnur Metin
Ege University, Fisheries Faculty , Turkey

Altan Lök
Ege University, Centre of Underwater Research and Application , Turkey

Ali Ulaş
Ege University, Centre of Underwater Research and Application , Turkey

Aytaç Özgül
Ege University, Centre of Underwater Research and Application , Turkey

Benal Gül
Ege University, Fisheries Faculty , Turkey

Cengiz Metin
Ege University, Centre of Underwater Research and Application , Turkey

Hüseyin Özbilgin
Mersin University, Fisheries Faculty , Turkey

Tuğçe Şensurat
Ege University, Graduate School of Natural and Applied Sciences , Turkey

Adnan Tokaç
Ege University, Fisheries Faculty , Turkey


This study aimed to determine the survival rates of three fish species, the brown comber (Serranus hepatus), black goby (Gobius niger) and annular seabream (Diplodus annularis), after their escape from a 40 mm stretched diamond mesh polyethylene (PE) codend. Experiments were carried out in the eastern Mediterranean in September 2007 using a conventional bottom trawl with 600 meshes around the mouth. A constant 15 min towing duration was used for all hauls. The towing speed varied between 2.0 and 2.5 knots. Codend covers, supported by two hoops, were used to retain escaping fish. At the end of each haul, these covers were detached from the codend, fixed to the sea floor at depths of 19 to 28 m, and then observed by the divers for a period of seven days. On the eighth day, all of the covers were lifted up and the survivors and mortalities were counted and measured. The mean survival percentages of open codend and experimental cages were found to be 97.1% and 98.3% for brown comber, 69.0% and 77.2% for black goby, and 97.5% and 98.6% for annular seabream respectively.


survival rate; escapes; trawl codend; discard and by-catch; Aegean Sea

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