Evaluating mandatory reporting of marine turtle bycatch in Atlantic Canadian fisheries

Abstract

Incidental capture of rare, threatened, and endangered marine species in commercial fisheries has prompted regional, national, and international monitoring and mitigation efforts with varying levels of success. Here we use leatherback sea turtle (Dermochelys coriacea) reports to evaluate federally-mandated Species at Risk Act (SARA) logbooks for reporting commercial fishing interactions with endangered species in Atlantic Canada. 503 leatherbacks were reported in SARA logbooks from 2006 to 2017. The majority of these (93%) corresponded to turtles captured in pelagic longline fisheries targeting swordfish and tunas. The remainder were reported from crab (1.2%), groundfish (1%), lobster (1.6%), mackerel (0.4%), whelk (2.6%), and herring (0.2%) fisheries, although fishing effort, gear configurations, and varying levels of observer coverage introduce biases that obscure conclusions about relative turtle-fishery interaction rates. Of 79 leatherback interactions with pelagic longlines reported by fisheries observers from 2006 to 2017, only 34% were documented in a corresponding SARA logbook entry. This finding, coupled with other sources of data which confirm regular bycatch of leatherbacks in Atlantic Canada, indicates that SARA logbooks, in their present form, underestimate true turtle-fishery interaction rates. Inconsistencies in SARA logbook requirements and reporting formats between management regions may further hinder the efficacy of this reporting tool. Potential improvements to the existing SARA logbook program are suggested; however, given the many limitations inherent in this type of reporting mechanism, alternative approaches to documenting bycatch of not only turtles, but other at-risk species, may ultimately prove more effective.