Both climate change and the fishing industry are posing a huge threat to fish and the Australian Federal Government must do more to manage the crisis, a leading fisheries expert has warned.
Tropical waters are emptying out as marine species are moving towards cooler water, and commercial fishing increases, says Dr Daniel Pauly, a principal investigator at research group Sea Around Us.
He said: "The depth, the distance from the coast, all of these were factors which protected fish. Now we go everywhere. Now nothing protects the fish
“Climate change is something that is already being perceived by fish. It’s already happening and they’re already moving. In temperate areas you will have the fish coming from a warmer area, and another one leaving.
"You’ll have a lot of transformation but they will actually - at least in terms of fishery - adapt. In the tropics you don’t have the replacement, you have only fish leaving.”
In 2016, Australia's federal government released a review suggesting its protective measures including no-fishing zones would be wound down. This would affect around 97,000sq km of ocean. A new plan is expected to be released soon.
Dr Pauly argues that more protective areas are needed - and are the only 'realistic' way of mitigating the current crisis.
While he didn't know whether it was the 'explosion' of the fishing industry or global warming that is having the biggest effect on fish numbers, both these issues must be addressed.
He believes that creating more - not less - marine reserves is the only viable option for governments to control damage in the meantime, which will increase populations in protected areas.
He said: "The only thing you can do – and it’s only mitigation – is keep the population big in the sea," he said, adding that populations 'bounce back quickly' when fishing stops. A larger population - and a higher variance of individual fish - helps the species evolve to adapt better to warmer temperatures.
He said: “Marine protected areas, marine areas, are one mitigating factor, and it’s the only thing you can do.”
Importance of policy
These designated areas must be managed properly, with appropriate policies in place - like maximum yields. Seasonal closures of areas is insufficient: when breeding fish are taken during 'open' seasons, this destroys the balance of populations.
Talking about partial protections like seasonal closes, Prof Jessica Meeuwig of the University of Western Australia’s marine futures lab, said: “It’s like having a Ferrari with a lawnmower engine – there’s no grunt.
“That’s one of the big things we need to start having a conversation about. When you say marine park, that it’s actually a marine park that’s protected.
"The Great Barrier Reef marine park, 67 per cent of it is open to fishing, and Ningaloo has 66 per cent open to fishing. It gives people a false sense of security because they think they’ve protected something when they haven’t.”