All primary production has environmental impacts and most have some impact on native mammal populations. On land, farmers can apply for permits to destroy kangaroos while no rules exist for vehicle road kill. However, in the marine environment the rules are much tougher. All marine mammals are afforded protection under the Environmental Protection and Biodiversity Conservation Act which requires that all reasonable steps be taken to reduce interactions. Fishery by-catch is considered within the Fisheries Management Act.
AFMA already run a process called an Ecological Risk Assessment (ERA) that considers the effects of commercial fishing on all species including marine mammals. The ERA is a tiered hierarchical framework that assigns species a low, medium or high risk so management actions can be prioritised. Management actions are tracked in each fishery’s by-catch and discard work plan.
Rules are already in place to protect Australian sea lions in the Gillnet, Hook and Trap Fishery (GHAT). Trigger limits have been set considering population structure and the number and location of breeding colonies.
Dolphin interactions sometimes occur in the Small Pelagic Fishery (SPF) and GHAT Fisheries and AFMA have implemented spatial management measures aimed to reduce the impact on dolphins. If an accidental dolphin mortality occurs in the SPF a vessel cannot return to one of seven management zones for six months. Similar rules exist in the GHAT. The precautionary principle states that if effects are unknown that management should be very conservative and to some extent this is why the limits on dolphins are so low. The method by which trigger limits for dolphins in particular are set have been questioned and the FRDC have released a report that aims to increase knowledge that can be used to set sensible limits for dolphins but also for other marine mammals.
The FRDC report calculates something called Potential Biological Removals (PBR) for several groups of marine mammals. PBR is the maximum number of animals, not including natural mortalities, that can be removed from a marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population. In no way is it a target or quota. PBR is widely used in the US where fisheries are classed as “strategic” if they cause mortality greater than 50% of the PBR and “non-strategic” if it is less than 50%. Management measures are prioritised accordingly.
Thankfully, the trawl sector does not have sea lion interactions and dolphin interactions are very rare (less than one per year) so the Association’s marine mammal focus is on both species of fur seals; Australian and New Zealand.
Using the lowest population estimate available of 87,000 seals the Australian fur seal PBR, or safe level of removal, is 2,623 to 4,721 individuals per annum. One third of fur seal interactions in the trawl fishery result in the seal being released and swimming away. The PBR calculation uses conservative population modelling estimates, the lowest estimate of stocks and does not consider the population of New Zealand fur seals – all of which make the PBR lower than it is likely in reality. Even with this level of precaution built into the numbers the PBR is thousands more than the trawl industry take. This outcome would make the trawl fishery classed as “non-strategic” or low priority in the US context.
The Association welcomes the report but continues to be committed to taking reasonable steps to reduce our environmental impacts. A long term project that aimed to reduce seal interactions by shortening trawl nets was unsuccessful. Growing seal populations make reducing interactions difficult. SETFIA members operate under a code of conduct that has reduced seal interactions and this code continues to be taught in training run by the Association. Training programs have already significantly increased our sector’s non-observed reporting of seals and are ongoing.
The report’s focus was mammals so did not consider seabirds but the Association’s target of reducing seabird interactions (versus bare warps) by more than 90% by May 2017 remains on track.