A comparative analysis of marine fish species susceptibilities to discard mortality: effects of environmental factors, individual traits, and phylogeny

Benoît, Hugues P.; Plante, Sébastien; Kroiz, Molly; Hurlbut, Thomas

doi:10.1093/icesjms/fss132

Cited by 56 publications

(61 citation statements)

References 34 publications

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“…Soak duration, depth of capture, ambient conditions, length, sex, hooking location, handling and release methods employed, duration out of the water, physical conditions onboard such as air temperature, and tackle remaining attached upon release can all have significant effects on the probability of post‐release survival (Davis ; Suuronen ; Benoît et al . ; Gilman et al . ).…”

Section: Discussionmentioning

confidence: 99%

A cross‐taxa assessment of pelagic longline by‐catch mitigation measures: conflicts and mutual benefits to elasmobranchs

et al. 2016

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Elasmobranch mortality in pelagic longline fisheries poses a risk to some populations, alters the distribution of abundance between sympatric competitors, changing ecosystem structure, processes and stability. Individual and synergistic effects on elasmobranch catch and survival from pelagic longline gear factors, including methods prescribed to mitigate bycatch of other vulnerable taxa, were determined. Overall relative risk of higher circle vs. J-shaped hook shark catch rates conditioned on potentially informative moderators, from 30 studies, was estimated using an inverse-precision weighted mixed-effects meta-regression modelling approach. Sharks had a 1.20 times (95% CI: 1.03-1.39) significantly higher pooled relative risk of capture on circle hooks, with two significant moderators. The pooled relative risk estimate of ray circle hook catch from 15 studies was not significant (RR = 1.22, 95% CI: 0.89-1.66) with no significant moderators. From a literature review, wire leaders had higher shark catch and haulback mortality than monofilament. Interacting effects of hook, bait and leader affect shark catch rates: hook shape and width and bait type determine hooking position and ability to sever monofilament leaders. Circle hooks increased elasmobranch catch, but reduced haulback mortality and deep hooking relative to J-shaped hooks of the same or narrower width. Using fish vs. squid for bait increased shark catch and deep hooking. Pelagic stingray (Pteroplatytrygon violacea) catch and mortality were lower on wider hooks. Using circle instead of J-shaped hooks and fish instead of squid for bait, while benefitting sea turtles, odontocetes and possibly seabirds, exacerbates elasmobranch catch and injury, therefore warranting fishery-specific assessments to determine relative risks.

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Section: Discussionmentioning

confidence: 99%

A cross‐taxa assessment of pelagic longline by‐catch mitigation measures: conflicts and mutual benefits to elasmobranchs

et al. 2016

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“…In contrast, and although perhaps not as accurate, indirect assessments generally are easier to achieve because they infer the fate of organisms, often by measuring either physical damage or vitality indices (Davis ; Benoît et al . , ; Raby et al . ) or physiological parameters indicative of stress (Patterson et al .…”

Section: Reviewmentioning

confidence: 99%

“…potassium, glucose and l ‐lactate) have all been used as surrogates of mortality (Benoît et al . , ; Frick et al . ).…”

Section: Reviewmentioning

confidence: 99%

Mitigating unaccounted fishing mortality from gillnets and traps

2013

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Gillnets and traps often are considered to have fewer holistic environmental impacts than active fishing gears. However, in addition to the targeted catches, gillnets and traps still cause unwanted mortalities due to (i) discarding, (ii) ghost fishing of derelict gear, (iii) depredation, (iv) escaping or dropping out of gear, (v) habitat damage, and potentially (vi) avoiding gear and predation and (vii) infection of injuries sustained from most of the above. Population‐level concerns associated with such ‘unaccounted fishing mortalities’ from gillnets and traps have been sufficient to warrant numerous attempts at mitigation. In this article, we reviewed relevant research efforts, locating 130 studies in the primary literature that concomitantly quantified mortalities and their resolution through technical modifications, with the division of effort indicating ongoing concerns. Most studies (85) have focused on discard mortality, followed by ghost‐fishing (24), depredation (10) and escape (8) mortalities. The remaining components have been poorly studied (3). All problematic mortality components are affected by key biological (e.g. species), technical (e.g. fishing mechanisms) and/or environmental (e.g. temperature) factors. We propose that these key factors should be considered as part of a strategy to reduce impacts of these gears by first assessing modifications within and then beyond conventional configurations, followed by changes to operational and handling practices. Justification for this three‐tiered approach is based not only on the potential for cumulative reduction benefits, but also on the likely ease of adoption, legislation and compliance.

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“…Without being able to explicitly quantify this due to small sample size for some species, survival seems to (at least partly) be related to body size as implied by the relatively high survival that larger organisms (e.g., C. conger , elasmobranchs) showed. A positive relation of survival with body size has been reported in the literature (Benoît et al., ; Davis, ; Depestele et al., ), however, for elasmobranchs one key factor is also the absence of swimbladder that sets them less susceptible to barotraumas (Broadhurst et al., ). In this study almost all bony fishes examined were physoclistous, barotraumas were evident and many individuals had difficulties in swimming when placed in tanks (e.g., they were upside down).…”

Section: Discussionmentioning

confidence: 95%

“…Discards estimates included in stock assessments usually assume that the whole discarded catch is dead or dies at sea (Mesnil, ). However, survival of individuals discarded at sea is substantial for several species (e.g., Benoît, Plante, Kroiz, & Hurlbut, ; Depestele, Desender, Benoît, Polet, & Vincx, ; Revill, ) while the inherent uncertainty of discards estimates—and their mortality—(Dickey‐Collas, Pastoors, & van Keeken, ) may further increase if survival is not taken into account. Survival is species dependent and is affected by numerous factors including biological factors, gears used and their technical characteristics, duration of the fishing operation, handling on board and environmental conditions (Broadhurst, Suuronen, & Hulme, ; ICES, ).…”

Section: Introductionmentioning

confidence: 99%

Preliminary assessment of discards survival in a multi-species Mediterranean bottom trawl fishery

et al. 2018

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Summary The EU Common Fisheries Policy (CFP) reform establishes a gradual landing obligation for stocks for which catch limits are set, and in the Mediterranean for species with Minimum Conservation Reference Size. However, the landing obligation will not apply for species with scientific evidence of high survival rates. Discards estimates usually assume that the whole discarded catch is dead or dies at sea. However, survival of individuals discarded at sea is substantial for several species. In the Mediterranean Sea, the information on this issue is very limited. The aim of this study is to perform a preliminary assessment of the short‐term survival of discards in the multi‐species bottom trawl fishery in the Eastern Ionian Sea, Greece. Experimental fishing was held in spring when no water column stratification was observed and in autumn when a seasonal thermocline was formed. The catch was sorted, the regularly discarded species/sizes were put in tanks and their survival was monitored in specific time intervals up to 72 hr. A seasonal effect was obvious with high mortality in autumn being attributed to high water temperatures. Survival was low or zero for most species, but was relatively high for certain species (e.g., annular seabream, Diplodus annularis (Linnaeus, 1758); European conger, Conger conger (Linnaeus, 1758); brown comber, Serranus hepatus (Linnaeus, 1758) among bony fishes) and broad taxonomic categories (elasmobranchs and most invertebrates) in spring or in both seasons. Poor survival was generally estimated for most species subject to the landing obligation (e.g., hake, Merluccius merluccius (Linnaeus, 1758)). The present study, even though preliminary, can be important for improving future works, for identifying species with high survival potential, and—to a lesser extent—for the implementation of the CFP.

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A comparative analysis of marine fish species susceptibilities to discard mortality: effects of environmental factors, individual traits, and phylogeny

Cited by 56 publications

References 34 publications

A cross‐taxa assessment of pelagic longline by‐catch mitigation measures: conflicts and mutual benefits to elasmobranchs

A cross‐taxa assessment of pelagic longline by‐catch mitigation measures: conflicts and mutual benefits to elasmobranchs

Mitigating unaccounted fishing mortality from gillnets and traps

Preliminary assessment of discards survival in a multi-species Mediterranean bottom trawl fishery

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