Sawfish bycatch mitigation workshop for northern Australian fisheries

The virtual workshop was attended by 49 people from 24 institutions including Commonwealth Scientific Industrial Research Organisation (CSIRO), Australian Fisheries Management Authority (AFMA), Fisheries Research and Development Corporation (FRDC), Northern Prawn Fishery Industry (NPFI), Great Barrier Reef Marine Park Authority (GBRMPA), James Cook University (JCU), Charles Darwin University (CDU), Australian Institute of Marine Science (AIMS), Queensland Department of Agriculture and Fisheries, Northern Territory Fisheries, Western Australia Department of Primary Industries and Regional Development, Western Australia Fishing Industry Council, Northern Territory Seafood Council (NTSC), Gulf of Carpentaria Commercial Fishing Association, Queensland Seafood Industry Association (QSIA) and representatives from the Department of Agriculture, Water and Environment (DAWE) Sustainable Fisheries and Biodiversity Conservation Division. The workshop was facilitated by Mr Dave Brewer, and Dr Sue Pillans was engaged as a visual artist to create a visual summary of the meeting.

State and Federal fisheries departments provided summaries of historical and recent sawfish bycatch reporting in gillnet and trawl fisheries. There was widespread acknowledgement that sawfish bycatch has historically been underreported in all fisheries. However, there have been recent improvements in some fisheries within the last two years.

Identified impediments to reporting included a fear that reporting would be penalised and a lack of trust between industry and management. Industry figures reported that the concept of data paucity leading to higher threat levels is not well understood at the boat level and there is a need to better communicate both the legal reporting requirements and the value of accurate data. Time constraints and overly complex and repetitive logbooks were also raised by industry groups as impediments to reporting.

There are currently no effective mitigation measures that prevent sawfish from becoming entangled in trawl or gillnets. Previous research in Australia demonstrated that electric pulses were unlikely to be useful in reducing sawfish bycatch in prawn trawlers. Current research on sawfish mitigation is focussed on prawn trawl gear and is investigating where sawfish are entangled and whether changes to the mesh can reduce entanglement. International research has found indications of reduced elasmobranch bycatch in gillnets fitted with green LED (light-emitting diode) lights; however, this would require testing in the turbid northern Australian conditions where sawfish occur.

To improve sawfish reporting and obtain an estimate of sawfish abundance and stock structure, the CSIRO proposed a large-scale collaborative project between industry, State and Commonwealth agencies, and research institutions led by CSIRO to gather tissue samples from across northern Australia. These would be used to conduct an assessment of sawfish abundance and stock structure using Close-Kin Mark-Recapture (CKMR), which is the only currently viable tool for this task. In addition to obtaining genetic samples, this project is aimed at improving logbook reporting and improving communication between industry, management and research in relation to sawfish and other threatened species.