Mortalities of fish escaping from square and diamond mesh codends in the Aegean Sea
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Published source details
Düzbastılar F.O., Özbilgin H., Aydın C., Metin G., Ulaş A., Lök A. & Metin C. (2010) Mortalities of fish escaping from square and diamond mesh codends in the Aegean Sea. Fisheries Research, 106, 386-392.
Published source details Düzbastılar F.O., Özbilgin H., Aydın C., Metin G., Ulaş A., Lök A. & Metin C. (2010) Mortalities of fish escaping from square and diamond mesh codends in the Aegean Sea. Fisheries Research, 106, 386-392.
Actions
This study is summarised as evidence for the following.
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Use a square mesh instead of a diamond mesh codend in a trawl net Action Link |
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Use a square mesh instead of a diamond mesh codend in a trawl net
A replicated, paired, controlled study in 2009 of an area of seabed in the Aegean Sea, Turkey (Düzbastılar et al. 2010) found that the short-term survival of two of six fish species after escaping from bottom trawls was higher in square mesh codends compared to diamond mesh codends. Overall, average survival rate was greater in square than diamond mesh codends for escaped red mullet Mullus barbatus (square: 95% of 950 fish; diamond: 81% of 225 fish) and blotched picarel Spicara maena (square: 97% of 460 fish; diamond: 91% of 174 fish). For annular seabream Diplodus annularis (82 fish) and common pandora Pagellus erythrinus (46 fish), survival rate was 100% for both codend types. In addition, average brown comber Serranus hepatus post-escape survival was 97% (of 332 fish) and 95% (of 126 fish) for square and diamond mesh codends, whilst all 355 scaldfish Arnoglossus laterna did not survive. For all species, most mortality occurred in the first 48 h after escape. Six, 15-min experimental bottom trawl deployments were done by research vessel off the southern coast of Yassica Island, Izmir Bay, in October 2009: three using a square mesh and three a diamond mesh codend (both 40 mm). Small mesh (24 mm), hooped detachable covers fitted over each codend collected escaped fish and at the end of each deployment were detached, sealed, and deployed on the seabed. Fish were fed and survival monitored in the anchored covers for seven days by divers.
(Summarised by: Leo Clarke)
