TY - JOUR
T1 - Short-term post-release mortality of skates (family Rajidae) discarded in a western North Atlantic commercial otter trawl fishery
AU - Mandelman, J. W.
AU - Cicia, A. M.
AU - Ingram, G. W.
AU - Driggers, W. B.
AU - Coutre, K. M.
AU - Sulikowski, J. A.
N1 - Funding Information:
The authors wish to thank the numerous undergraduate, post-graduate, and graduate students from the Sulikowski Lab at the University of New England (UNE) and New England Aquarium (NEAq) for assistance in fieldwork during the course of the study. Deckhands aboard the F/V Mystique Lady and F/V Lady Victoria also provided invaluable support during field operations. Funding for this work was provided by NOAA National Marine Fisheries Service Northeast Region (Saltonstall–Kennedy (S–K) award to J.W.M.). In addition, A.M.C. was partially supported by a National Science Foundation Graduate Research Fellowship under Grant No. DGE-1144249 . Animal care and use for various portions of this work was sanctioned by both UNE (IACUC approval # UNE03-2010) and the NEAq (IACUC approval # 08-05).
PY - 2013/3
Y1 - 2013/3
N2 - Due to market and regulatory factors, Rajidae skates are routinely discarded by commercial otter trawlers in the western North Atlantic. Accounting for post-release mortality is therefore essential to total fishing mortality estimates, stock status and management of this group of fishes. However, despite a presumed species-specific range in tolerance, few studies have investigated the short-term post-release mortality among skates indigenous to the western North Atlantic following capture by mobile fishing gears, and never in the Gulf of Maine. This study addresses this shortfall for the prohibited thorny skate, Amblyraja radiate and smooth skate, Malacoraja senta, and the targeted winter skate, Leucoraja ocellata, and little skate, Leucoraja erinacea. Of 1288 skates evaluated, negligible immediate mortality was observed at the time of capture, even in relation to the largest catches and/or most prolonged tows. However, injury frequency was moderate, with highest levels in the smooth (60%) and thorny (52%) skates. Aside from the smooth skate (59%), 72. h mortality rates were low overall (19% across all species when accounting tow durations indicative of the fishery), with the winter skate (8%) exhibiting the lowest levels. Logistic regression modeling revealed tow duration as the most universal predictor of condition and 72. h mortality, while catch biomass, sex, temperature changes, and animal size also held influence in certain species. Although in general the studied species appear more resilient to trawl capture and handling than previously estimated, interspecific differences must be accounted for when managing this group.
AB - Due to market and regulatory factors, Rajidae skates are routinely discarded by commercial otter trawlers in the western North Atlantic. Accounting for post-release mortality is therefore essential to total fishing mortality estimates, stock status and management of this group of fishes. However, despite a presumed species-specific range in tolerance, few studies have investigated the short-term post-release mortality among skates indigenous to the western North Atlantic following capture by mobile fishing gears, and never in the Gulf of Maine. This study addresses this shortfall for the prohibited thorny skate, Amblyraja radiate and smooth skate, Malacoraja senta, and the targeted winter skate, Leucoraja ocellata, and little skate, Leucoraja erinacea. Of 1288 skates evaluated, negligible immediate mortality was observed at the time of capture, even in relation to the largest catches and/or most prolonged tows. However, injury frequency was moderate, with highest levels in the smooth (60%) and thorny (52%) skates. Aside from the smooth skate (59%), 72. h mortality rates were low overall (19% across all species when accounting tow durations indicative of the fishery), with the winter skate (8%) exhibiting the lowest levels. Logistic regression modeling revealed tow duration as the most universal predictor of condition and 72. h mortality, while catch biomass, sex, temperature changes, and animal size also held influence in certain species. Although in general the studied species appear more resilient to trawl capture and handling than previously estimated, interspecific differences must be accounted for when managing this group.
KW - Discard
KW - Mortality
KW - Post-release
KW - Skate
KW - Tow
KW - Trawl
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U2 - 10.1016/j.fishres.2012.09.020
DO - 10.1016/j.fishres.2012.09.020
M3 - Article
AN - SCOPUS:84872413761
SN - 0165-7836
VL - 139
SP - 76
EP - 84
JO - Fisheries Research
JF - Fisheries Research
ER -