Survival of discarded plaice ( Pleuronectes platessa ) from Norway lobster ( Nephrops norvegicus ) otter-trawl fishery

Marc Eskelund, Caroline Methling, Peter Vilhelm Skov, Niels Madsen*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

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.
Original languageEnglish
JournalJournal of Applied Ichthyology
Volume35
Issue number3
Pages (from-to)645-654
ISSN0175-8659
DOIs
Publication statusPublished - 2019

Keywords

  • Bycatch
  • Discard ban
  • Discard survival
  • Injury assessment
  • Landing obligation
  • RAMP
  • Reflex action mortality predictor
  • Vitality assessment

Cite this

@article{07f7161706d8440b8ee9ee5faa0debaa,
title = "Survival of discarded plaice ( Pleuronectes platessa ) from Norway lobster ( Nephrops norvegicus ) otter-trawl fishery",
abstract = "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.",
keywords = "Bycatch, Discard ban, Discard survival, Injury assessment, Landing obligation, RAMP, Reflex action mortality predictor, Vitality assessment",
author = "Marc Eskelund and Caroline Methling and Skov, {Peter Vilhelm} and Niels Madsen",
year = "2019",
doi = "10.1111/jai.13888",
language = "English",
volume = "35",
pages = "645--654",
journal = "Journal of Applied Ichthyology",
issn = "0175-8659",
publisher = "Wiley-Blackwell",
number = "3",

}

Survival of discarded plaice ( Pleuronectes platessa ) from Norway lobster ( Nephrops norvegicus ) otter-trawl fishery. / Eskelund, Marc; Methling, Caroline; Skov, Peter Vilhelm; Madsen, Niels .

In: Journal of Applied Ichthyology, Vol. 35, No. 3, 2019, p. 645-654.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Survival of discarded plaice ( Pleuronectes platessa ) from Norway lobster ( Nephrops norvegicus ) otter-trawl fishery

AU - Eskelund, Marc

AU - Methling, Caroline

AU - Skov, Peter Vilhelm

AU - Madsen, Niels

PY - 2019

Y1 - 2019

N2 - 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.

AB - 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.

KW - Bycatch

KW - Discard ban

KW - Discard survival

KW - Injury assessment

KW - Landing obligation

KW - RAMP

KW - Reflex action mortality predictor

KW - Vitality assessment

U2 - 10.1111/jai.13888

DO - 10.1111/jai.13888

M3 - Journal article

VL - 35

SP - 645

EP - 654

JO - Journal of Applied Ichthyology

JF - Journal of Applied Ichthyology

SN - 0175-8659

IS - 3

ER -