THERE’S plenty of debate about where “trigger points” should be set for action on limiting the harvest, both commercial and recreational, for key species. Right now in NSW, there’s plenty of concern about the sustainable status of some of those species, particularly mulloway, yellowtail kingfish and snapper, and that’s led to some “robust” exchanges even in the comments sections of this website. Some rec fishers reckon the concern is an over-reaction, some say the situation is actually worse than acknowledged. Commercial operators in NSW actively oppose lifting of size limits for these fish to levels which will give majority of females a chance to breed at least once and to date fisheries managers haven’t been game to confront the issue. The old “this will ruin my livelihood” argument gets dragged out and often works. And rec fishers aren’t all innocent either. Reduced bag limits are predictably criticised by some.
But at the end of the day all the sustainable certifications in the world won’t mean anything if there aren’t sufficient biomasses of fish. And fisheries managers have imperatives other than straight species conservation to worry about… political, economic and societal. For example, to maximise economic returns and grow export earnings and not to put those associated with the fishing industry out of work.
But get stock management wrong and disaster follows. The classic case is the total collapse of the Newfoundland cod fishery at the cost of 60,000 jobs. Those managing that fishery thought their quotas and other harvest controls would be enough to ensure the fishery’s future. Wrong, just like we were in NSW with the south coast SBT and gemfish fisheries.
So how do you manage stocks? It’s not so simple as using one size-fits-all formulas. Golden snapper can take 40 years to grow to peak harvestable size. Mahi mahi and cobia can do that in a year.
The UN’s Food and Agriculture Organisation (FAO) provides guidelines for stock status reporting. If a current stock biomass is found to be less than 40 per cent of unfished biomass, the stock is “overexploited”. If between 40- and 60 per cent, “fully exploited”. If above 60 per cent, “underexploited”. All very useful, as long as you’ve got the resources and expertise to do the measurement and data interpretation, which a large part of the world doesn’t. And the political will to act on the findings.
Now underneath all of this exists the trigger reference point, which is the percentage of the unfished biomass at which point a fisheries manager needs to take remedial action – total closure, a temporary closure, a fishing zone restriction. In Australia, this “panic point” has traditionally been 20 per cent. And that’s the figure that we and many fisheries scientists and Australian fisheries managers (at least in private conversations) reckon is dangerously low.
