Assessment and benefits of damage reduction in prawns due to use of different bycatch reduction devices in the Gulf of Carpentaria, Australia

The use of bycatch reduction devices (BRDs) and turtle exclusion devices (TEDs) will be compulsory in the Northern Prawn Fishery of Australia by the year 2000. These devices may also benefit fishers by excluding large animals that can damage prawns in the trawl and thereby improve catch quality, and hence value. This study measures the reduction in physical damage to prawns caught with BRD-fitted nets compared to a standard codend. The measure of damage was that a prawn had one or more of the types of damage that, in commercial fishers, would condemn it to a less valuable soft and broken category. The change in prawn damage ratio was between 6.1% and 34.7% depending on the BRD being used. The total catch weight and weight of large animals (>5 kg) were significantly reduced with a grid (excluder device) in the net. The best BRD for retention of prawns and damage reduction was the Super Shooter + Fisheye. The economic value of reducing prawn damage was calculated from a combination of the percentage reduction in damage and the price difference between 10 kg soft and broken prawns and higher-priced, finger-laid prawns in 1.5, 3.0 or 5.0 kg packs. The increased value of catches from reduced prawn damage in two BRDs that did not significantly affect prawn catches was conservatively estimated to be $735 per week, which is more than the cost of the BRD. (C) 2000 Elsevier Science B.V. All rights reserved.