ASFB Home > 2003 > Biological Invasions: Consequences for Parasites, Pathogens, Emerging Diseases, and Fisheries in the Marine Environment.

Reducing bycatch in Queensland’s trawl fishery – experimental charters using nets with square mesh codends show promising results

Matthew Campbell, Keith Chilcott, Anthony Courtney, Shane Gaddes, Peter Kyne, Darren Roy, Mark Tonks, Clive Turnbull* and Claire van der Geest*

Queensland Department of Primary Industries, Agency for Food and Fibre Sciences, Southern Fisheries Centre, PO Box 76 Deception Bay, 4506 Queensland
*Northern Fisheries Centre, PO Box 5396, Portsmith, 4807 Queensland
Email: Tony.Courtney@dpi.qld.gov.au

Benthic trawl fisheries, such as those for prawns and scallops on the Queensland, generally produce large amounts of bycatch, which is comprised of hundreds of species of small fish and invertebrates. The weight of the bycatch often exceeds the target catch. A research project funded by FRDC has been quantifying the catch rates and composition of bycatch in the fishery and testing a range of bycatch reduction devices (BRDs). Results from research charters indicate that bycatch can be significantly reduced by using specific devices, without incurring any loss of target catch. The most promising results thus far have been achieved by using nets that have both turtle excluder devices (TEDs) and square mesh codend BRDs installed. Basically, TEDs exclude large animals such as turtles, rays, sharks and sponges, while square mesh codends remove small species of fish and invertebrates. In the deep-water eastern king prawn fishery a 28% reduction in bycatch weight was achieved using these devices with no prawn loss compared to the standard net. In the scallop fishery a massive 77% reduction in bycatch weight was achieved with the same devices. The square mesh codend had the additional benefit of reducing the catch rate of undersize scallops by about 20%. When applied across the entire fishery these estimated reductions equate to lowering the bycatch by several thousand tonnes annually. While there are now legislative requirements for fishers to use BRDs throughout the Queensland trawl fishery, the main challenge is in persuading a sceptical industry to use the most effective devices.

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