Survival and recovery of longline- and pot-caught cod (Gadus morhua) for use in capture-based aquaculture (CBA)

Humborstad, Odd-Børre; Breen, Michael J.; Davis, Michael W.; Løkkeborg, Svein; Mangor‐Jensen, Anders; Midling, Kjell Ø.; Olsen, Rolf Erik

doi:10.1016/j.fishres.2015.09.001

Cited by 29 publications

(18 citation statements)

References 31 publications

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“…Previous studies have shown reflex impairment as a tool to predict stress and even delayed mortality in different species of fish (Davis, ; Humborstad et al, , ; Methling et al, ). Reflex impairment alone was not a strong indicator of delayed mortality in this study.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2019

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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.

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Section: Discussionmentioning

confidence: 99%

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

et al. 2019

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“…As a method of assessing vitality, each captured fish was assigned an injury condition and tested for reflex responses ( Barkley and Cadrin, 2012 ; Humborstad et al , 2016 ). Injury condition and reflex responses were analyzed separately to distinguish the effects of physical trauma from behavioural impairment.…”

Section: Methodsmentioning

confidence: 99%

“…Recent studies have attempted to quantify the stress response associated with the capture and handling process. For example, physical responses such as external injury and reflex impairment have been utilized to assess the stress of capture in teleost species including yellowtail flounder ( Limanda ferruginea ) ( Barkley and Cadrin, 2012 ), Atlantic cod ( Gadus morhua ) ( Humborstad et al , 2016 ) and bluegill ( Lepomis macrochirus ) ( Lennox et al , 2015 ). In addition to utilizing overt trauma as predictors of mortality, physiological responses to the capture and handling process have been quantified via changes in such biochemical markers as cortisol, lactate, glucose and mean corpuscular haemoglobin content (MCHC) that can aid in quantifying stress ( Donaldson et al , 2013 ; Uhlmann et al , 2015 ; Barkley et al , 2017 ).…”

Section: Introductionmentioning

confidence: 99%

The effect of capture and handling stress inLophius americanusin the scallop dredge fishery

Weissman

Mandelman

Rudders

et al. 2018

Conservation Physiology

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“…Milliken et al, 1999Milliken et al, , 2009Pálsson et al, 2003;Suuronen et al, 2005;Ingó lfsson et al, 2007;Humborstad et al, 2016), only one has addressed recreational fisheries (11% overall DM in the Baltic Sea; Weltersbach and Strehlow, 2013). Although not primarily focused on providing representative DM rate estimates, other recreational cod DM studies have been essential in understanding sublethal factors associated with capture-and-release events (Ferter et al, 2015a, b).…”

Section: Introductionmentioning

confidence: 99%

Estimating and mitigating the discard mortality of Atlantic cod (Gadus morhua) in the Gulf of Maine recreational rod-and-reel fishery

Capizzano

Mandelman

Hoffman³

et al. 2016

ICES Journal of Marine Science

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In recent years, the recreational contribution to the total catch of Atlantic cod (Gadus morhua) in the Gulf of Maine (GOM) has increased with recreational discards outnumbering recreational landings by 2:1. However, the discard mortality (DM) rate of cod released in the recreational fishery remains poorly understood, thus contributing to the uncertainty in stock assessments and fishery management plans. The current study examined the capture-related factors most detrimental to cod DM in the GOM recreational rod-and-reel fishery. Atlantic cod (n ¼ 640; 26.0-72.0 cm) were angled from June-October 2013 on southern Jeffreys Ledge in the western GOM using fishing gear representative of the local recreational fishery. A subset (n ¼ 136) was also tagged with pressure-sensing acoustic transmitters before being released into an acoustic receiver array (n ¼ 31) deployed to monitor survival up to 94 days. To properly model DM up to the fishery-wide level, all cod were visually assessed for capture-related injuries according to a four-level injury score index. Mean tackle-specific DM rates of 15.4 and 21.2% were estimated for bait-and jig-captured cod, respectively, with an overall 16.5% mean DM rate for the 2013 GOM recreational cod fishery. Twenty-nine cod tagged with acoustic transmitters were identified as dead, where the majority ( 90%) died within 16 h post-capture. Upon evaluation with a specifically adapted parametric survival analysis, greater incidence of mortality was attributed to the capture and handling process (rather than release) for moderately and severely injured cod. Based on the capture-related factors associated with the highest injury rates, we recommend minimizing fight and handling times, avoiding areas with small cod, educating inexperienced anglers, and favouring bait over jigs to mitigate mortality. Results will continue to inform the development of fishery management plans and enhance survival through dissemination of "best practice" techniques to fishery stakeholders.

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Survival and recovery of longline- and pot-caught cod (Gadus morhua) for use in capture-based aquaculture (CBA)

Cited by 29 publications

References 31 publications

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

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

The effect of capture and handling stress inLophius americanusin the scallop dredge fishery

Estimating and mitigating the discard mortality of Atlantic cod (Gadus morhua) in the Gulf of Maine recreational rod-and-reel fishery

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