Bycatch reduction devices (BRDs) to reduce the incidental catch of cuttlefish in the Spencer Gulf prawn fishery

A study was conducted aboard vessels from the South Australian Spencer Gulf prawn fishery to examine the utility of a mechanical-separating bycatch reduction device. The fishery targets prawns but has bycatch of giant cuttlefish (Sepia apama) and blue swimmer crabs (Portunus armatus). Conventional codends were tested against small and large Nordmore-grids set at high and low grid angles. Both grids resulted in bycatch reductions. The number and weight of cuttlefish were reduced by 50.4% and 59.7%, respectively, when the small grid was used. The large grid resulted in a reduction of 33.5% in number and 36.6% in weight of cuttlefish. Crab bycatch was reduced by 40.2% (number) and 47.5% (weight) when the small grid was used, and 40.9% (number) and 38.1% (weight) when the large grid was used. A reduction in prawn catch (weight) was observed when the small grid was used compared with the large and control grid.