Mortality of herring escaping from pelagic trawl codends
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Published source details
Suuronen P., Erickson D.L. & Orrensalo A. (1996) Mortality of herring escaping from pelagic trawl codends. Fisheries Research, 25, 305-321.
Published source details Suuronen P., Erickson D.L. & Orrensalo A. (1996) Mortality of herring escaping from pelagic trawl codends. Fisheries Research, 25, 305-321.
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This study is summarised as evidence for the following.
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Use a larger mesh size Action Link |
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Use a larger mesh size
A replicated, controlled study in 1992 in an area of seabed in the Baltic Sea, Finland (Suuronen et al. 1996) found that a larger mesh size increased the size at which herring Clupea harengus could escape from a pelagic trawl net, and for smaller fish post-capture survival was similar between mesh sizes. The numbers at length of herring between 12–17 cm that escaped from a 36 mm codend ranged from 20–1,200, whereas almost no fish of these sizes escaped from a 26 mm mesh (data were not tested statistically). However, there was no difference in average percentage mortality of small (<12 cm) herring escapees between the 36 mm and 26 mm mesh codends and compared to herring escaping from an open codend (data reported as statistical model results). A total of 37 trawl deployments of 15–30 minutes were made using three codend types (36 mm, 26 mm and open) in April–June 1992 from a commercial trawler. A small mesh (14 mm) codend cover retained the escaping fish. After each deployment escaped herring were released into a separate cage (average 760 herring/cage) suspended 7–17 m below the surface. Cages were recovered in blocks at intervals between 1.5–9 days and mortality recorded.
(Summarised by: Chris Barrett)
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