Madigan DJ, Devine BM, Weber SB, Young AL, Hussey NE

Combining telemetry and fisheries data to quantify species overlap and evaluate bycatch mitigation strategies in an emergent Canadian Arctic fishery

Greenland halibut Reinhardtius hippoglossoides support important Arctic fisheries, with development of inshore summer fisheries in response to shortening Arctic sea-ice seasons. Deep-set longline fisheries result in bycatch of Greenland shark Somniosus microcephalus and Arctic skate Amblyraja hyperborean, raising concerns for increasing bycatch with fisheries expansion. Madigan and colleagues combined data from animal-borne electronic tags and exploratory fishery catch rates to assess strategies for bycatch mitigation. Electronic tags showed that Greenland shark use of peak Greenland halibut depths (>1000m) is rare, but fisheries data showed that deep dives were frequent enough to drive high Greenland shark bycatch. As such, targeting specific depths is unlikely to reduce bycatch and other measures (reduced soak times, gear modification) should be considered.

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