Evaluating the Condition and Discard Mortality of Winter Skate, Leucoraja Ocellata, Following Capture and Handling in the Sink Gillnet Fishery

One of the most significant issues effecting marine fisheries management is the immediate and delayed mortality of fish that are discarded (as bycatch) after capture. Sink gillnets are used to target skates, monkfish, and other demersal species in the northeast (NE).  Despite the widespread use of this gear type, information regarding post release mortality (PRM) for any species captured by this method is lacking, and for winter skates it is assumed to be 50%. Given this uncertainty, the authors were funded to quantify the (immediate) at-vessel and short-term delayed (discard) mortality rates from sink gillnet capture for this skate species. A total of 27 trips, with soak times ranging from one to 14 days, have been conducted as part of this research project. Preliminary data obtained from various environmental temperature and soak times suggests that PRM is less than 10%. In addition, injury code and soak time appear to have a direct effect on the discard mortality of winter skate. Final results presented at AFS 2016 will evaluate the factors that will allow the PI’s to refine mortality estimates to the conditions in the fishery and to identify potential avenues to improve the chances of successful live release.