Bluewater Magazine Issue 122

Both commercial and recreational fishers all have the same purpose – to catch their target species.

Unfortunately, as part of fishing operations, there may be the unintended catch of other species, also known as bycatch.  While levels of bycatch can vary depending on the type of fishing gear used and areas fished, in recent years, the commercial industry, together with scientists and fisheries regulators have worked hard to manage bycatch levels. As a result, there are now many ways that bycatch can be reduced with fairly low effort and cost.

Bycatch management is a high priority for the Australian Fisheries Management Authority (AFMA) and we are always looking for new innovations or ways to improve the efficiency of Australia’s commercial fishing, but without imposing high costs to fishing boats. AFMA defines bycatch as, ‘species that physically interact with fishing vessels and/or fishing gear and are not usually kept by commercial fishers’. This means that bycatch can be alive or dead and can include crustaceans, sharks, molluscs, marine mammals, reptiles and birds.

The pelagic longlines used by Australia’s tuna fleet in the Eastern Tuna and Billfish Fishery (ETBF) are a reasonably selective fishing method with relatively low bycatch compared to other commercial fishing methods. Pelagic longline fishing incorporates a long length of mainline (up to 90 km) with numerous branch lines with hooks attached that hang in the water column (Figure. 1). Tuna and billfish species opportunistically take the baits, but other species may be attracted to them as well.

Some shark species and turtles can also end up hooked or tangled in the line, along with other fish species. In most cases, these animals are released alive when the longline is hauled up by the boat. For example, observer data from the last 10 years shows that there has been an average of five turtles caught in the ETBF per year and of these, 75 per cent have been released alive, with the numbers continuously improving. These figures are significantly lower than many other international fisheries where there is limited data.

As most bycatch in the ETBF is brought to the boat alive, it is crucial that any animals are released with minimal harm. To aid this, AFMA has supplied ETBF fishers with line cutter and de-hooking devices that enable crew to release bycatch species as safely as possible and in a way that maximises the survival of the animal. Most fishers in the ETBF now use circle hooks to further reduce the catch of turtles. AFMA has also banned wire trace to reduce the retention of any sharks that might be caught.

Bycatch can also be caught near the surface as the lines are being set, as has historically been the case for seabirds. As mentioned in a previous Bluewater article, the ETBF used to catch large number of seabirds. To address this problem, AFMA implemented a number of measures to enable industry to reduce their likelihood of catching birds. These measures included weighting branch lines so that baited hooks are pulled down quickly in the water column, out of the reach of diving seabirds; tori lines that hang above the water surface and have a series of streamers attached to act as a scaring device for birds; and restrictions on when fish offal can be thrown overboard, i.e. not when the longline is being shot into the water with all the hooks baited.

Current levels of bycatch in the ETBF are low and animals such as seabirds, turtles and most sharks are now rarely caught by fishers. It is likely that many recreational fishers encounter the same types of bycatch when fishing for tuna and billfish species off the east coast of Australia. By being aware of what other species might be around your fishing experience and efficiency could be even better, with just a few small adjustments to your gear or fishing location.

AFMA continuously collects data on all catch of commercial boats and in the ETBF, electronic monitoring has been recently implemented. This allows AFMA to monitor all catch from tuna longlines through cameras and sensors. The footage is reviewed regularly, with shots selected at random for analysis and comparison with the associated logbook report submitted by fishers. Using this technology, AFMA can much more accurately monitor all bycatch in near real-time and be more proactive in our management responses.

In addition to electronic monitoring as a proactive tool to keep on top of bycatch management in the ETBF, AFMA has developed a new Ecological Risk Assessment process. This takes into account all the species caught and recorded in the ETBF and analyses their level of risk of impact from longline fishing operations. Ecological Risk Assessments are run by the CSIRO. Through this rigorous, science-based assessment process, AFMA can determine exactly which species, habitats and communities are at the highest risk of being impacted by longline fishing.

The results of the previous Ecological Risk Assessment indicated that birds, turtles and sharks are the groups of species at the highest risk from tuna fishing. From these results, AFMA has developed appropriate risk management strategies, tailored to specific species, which further reduce any impacts from fishing. Specific Ecological Risk Management strategies that have been developed in the past for the ETBF have included increased monitoring of catch, either through on-board observers or now electronic monitoring, or with various mitigation requirements such as those mentioned above for turtles, sharks and seabirds.

AFMA has recently developed a new framework for Ecological Risk Assessments and Management strategies, but it has streamlined the process and made the results more accurate and appropriate for each fishery. This framework is still yet to be applied to most Commonwealth fisheries, but already results are looking positive for the ETBF. However, there is always room for improvement and with collaboration from the ETBF industry through the new association – Tuna Australia – AFMA will continue to help the fishing industry minimise their bycatch over the long term.

Birds, turtles and sharks are also caught by game fishers and the results from the Ecological Risk Assessment highlight the need for all fishers to release these animals alive where possible. The GFAA Code of Conduct already states that direct effects from recreational fishing on seabirds, reptiles and mammals should be minimised.

The continued stewardship of the oceans by all fishers will ensure that impacts on wildlife are minimised and shared access to fisheries resources remains for all. If you’re interested in further information about bycatch in Commonwealth commercial fisheries or the ecological risk assessment and management process, head to the AFMA website – or AFMA’s Facebook page.