Eayrs, S., Hai, N. P., and Ley, J. 2007. Assessment of a juvenile and trash excluder device in a Vietnamese shrimp trawl fishery. – ICES Journal of Marine Science, 64: 1598–1602.In this study, we (i) identified why Vietnamese shrimp fishers land juvenile fish illegally; (ii) identified groups of fishers that would use a bycatch reduction device (BRD) to exclude these fish; (iii) studied the hydrodynamic performance of a juvenile and trash excluder device (JTED) in a flume tank; and (iv) assessed the performance of this device under commercial fishing conditions. Based on the responses of 65 fishers to a questionnaire, we found that juvenile fish are now an important economic component of the total catch, and that fishers operating larger boats were more willing to use a JTED to exclude these fish than fishers operating smaller boats. The hydrodynamic study of a JTED identified the location of low-velocity regions around the device and codend, and this information can be used to identify the location of a secondary BRD to allow more fish to escape. The at-sea assessment of this device found that 73% of juvenile fish, 16% of valuable fish, and 8% of shrimp were excluded by the JTED, although most valuable fish and shrimp were smaller than the minimum legal landing size. Overall, this loss represents a 9% reduction in revenue. Yield-per-recruit analysis indicated that this could be offset by not catching fish less than the minimum legal landing size.
Keywords: bycatch reduction device; fishery; flume tank; hydrodynamic performance; juvenile and trash excluder device; shrimp trawl; Vietnam
Journal Article. 3710 words. Illustrated.
Subjects: Environmental Science ; Marine and Estuarine Biology
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