Effect of PA and PE material on codend selectivity in Turkish bottom trawl
Published source details
Tokaç A., Özbilgin H. & Tosunoğlu Z. (2004) Effect of PA and PE material on codend selectivity in Turkish bottom trawl. Fisheries Research, 67, 317-327.
Published source details Tokaç A., Özbilgin H. & Tosunoğlu Z. (2004) Effect of PA and PE material on codend selectivity in Turkish bottom trawl. Fisheries Research, 67, 317-327.
This study is summarised as evidence for the following.
Use a larger mesh sizeAction Link
Use a larger mesh size
A replicated, controlled study in 2002 in an area of seabed in Izmir Bay in the Aegean Sea, Turkey (Tokac et al. 2004) found that using a larger mesh size codend and different netting material in a trawl net improved the size-selectivity of annular sea bream Diplodus annularis and common pandora Pagellus erythrinus compared to a smaller commercial mesh size and netting type. For sea bream, irrespective of twine type, the length at which fish had a 50% chance of escape was higher in a 44 mm mesh codend (10.3 cm) compared to the standard 40 mm (8.8 cm) and a 36 mm mesh (8.4 cm) codend. For pandora, the length at 50% escape was also greater with the larger mesh than the standard (44 mm: 13.8 cm, 40 mm: 10.8 cm). However, compared to the standard it was also greater in a smaller mesh of a different twine type (36 mm: 12.4 cm). Data were collected from 23 experimental trawl deployments conducted from a research vessel in February and March 2002. Three codend types were tested: 44 mm and 36 mm mesh size multi-filament polyamide netting, and a commercially used 40 mm multi-monofilament polyethylene netting (see paper for specifications). Small mesh (24 mm) codend covers retained escaping fish. Tow duration was 45 minutes with an average tow speed of 2.4 knots.
(Summarised by: Chris Barrett)