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Survival of discarded plaice ( Pleuronectes platessa ) from Norway lobster ( Nephrops norvegicus ) otter‐trawl fishery
Author(s) -
Eskelund Marc,
Methling Caroline,
Vilhelm Skov Peter,
Madsen Niels
Publication year - 2019
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1111/jai.13888
Subject(s) - pleuronectes , nephrops norvegicus , fishery , otter , bycatch , biology , fishing , seabird , gadus , predation , discards , fish <actinopterygii> , ecology , crustacean , decapoda
The introduction of landing obligations in the European Union common fisheries policy, has increased the focus on discard survival. Since species with scientifically proven high survival rates may be exempted from the landing obligations, the economic significance for the fishing industry is large. Landing obligations include individuals below the minimum conservation reference size (MCRS), which are not allowed to be sold for human consumption. The Norway lobster ( Nephrops norvegicus ) fishery is a high value fishery, but with a substantial amount of bycatch of plaice ( Pleuronectes platessa ) below the MCRS. In the present study, observations were made on the short‐term survival of plaice at or below the MCRS, discarded from a small otter board trawler targeting Nephrops in Skagerrak (ICES 3a). The average short‐term survival of plaice was 15% at haul level, ranging from 0% to 39%, after 10 days of captive observation. Survival significantly decreased with time on deck and the retention of debris in the codend ( p < 0.0001), while survival was not correlated to size. Vitality assessments, using a combined reflex impairment and injury score, were tested as predictor of survival and were significantly associated to survival ( p < 0.0001) both for individual fish and when grouped by hauls. Seabird predation behaviour was assessed and it was estimated that seabirds predated or pursued 85% of discarded plaice below the MCRS.