A novel bycatch reduction device (BRD) and its use in a directed fishery for non-indigenous green crabs (C. maenas) in Atlantic Canada

The European green crab (Carcinus maenas) is one of the world's most successful invasive species. Even though most attempts at control of this species have failed, a recently implemented fishery in Atlantic Canada aims to control its populations and mitigate its negative effects. The use of fyke nets to capture green crabs could reduce the cost of fishing and increase the financial incentive to harvest this species. However, these nets are currently not permitted for fishing this species because they potentially capture large amounts of bycatch in a sensitive ecological zone. Hence, the primary goal of this study was to design and assess the effectiveness of a novel bycatch reduction device (BRD) installed on traditional fyke nets. Fyke nets were deployed in pairs at four shallow subtidal sites in eastern Prince Edward Island and sampled over 16 consecutive days in summer 2016. Both catch (green crab) and bycatch counts in the original fyke nets were significantly higher than in the nets equipped with a BRD. However, bycatch diversity was significantly lower in the BRD equipped nets, and proportionally less detrimental to three economically and ecologically important bycatch species.