An Australian-led study shows that protecting more fish could secure the livelihoods of millions of people.

Scientists say 200 countries currently protect 10 per cent of national marine areas as part of the Convention on Biological Diversity, but they should aim to secure 20 - 30 per cent.

Specifically, the report by the University of Queensland, University of Melbourne and others says that a strict focus on areas that are unprotected fishing grounds, particularly where biodiversity and fisheries are threatened, should actually  increase long-term catches of otherwise unregulated fisheries. 

UQ School of Biological Sciences researcher Dr Nils Krueck says it is a hard sell.

“Potential declines in fisheries catches are a concern wherever marine reserves are enforced,” he said. 

“However, specifically in some of the world’s most biodiverse and poorly managed areas, closing more than 10 per cent of fishing grounds [like the current Aichi Biodiversity Target for the protection of 10 per cent of coastal marine regions] is likely to benefit fishers in the long run. 

“Coral reef fisheries in much of the South-East Asian Coral Triangle region, including Indonesia, Malaysia and the Philippines, are a good example of this situation. 

“More and more species are now lost and sustainability is of grave concern, because catch limits and other traditional fisheries management tools are difficult to enforce.” 

UQ researcher Professor Peter Mumby said closing 20-30 per cent of fished habitats was a comparatively simple management action. 

“It will not solve the fisheries crisis in the Coral Triangle, but our findings highlight that coral reef fisheries in particular are likely to benefit from fish population recovery and the subsequent export of young fishes from reserves to fished areas,” he said. 

“Effective reserve coverage policies could help millions of people in the Coral Triangle region who rely on small-scale coral reef fisheries for food and livelihoods.”

Professor Mumby said previous studies raised valid concerns that designating some of the marine area for protection could reduce the potential value of a fishery.

However, he said marine reserves were one of the few means of managing fisheries where conventional regulations of effort are infeasible; either too costly, unenforceable, or both. 

“Based on an analysis of thousands of fisheries scenarios, this study finds that even closing more than 30 per cent of fished areas can produce net benefits to fisheries, particularly when populations are heavily over-exploited,” Professor Mumby said. 

“Achieving much higher effective reserve coverages than the currently estimated one to two per cent on coral reefs can help protect species, and rebuild and sustain fisheries catches.”

The study, published in the journal PLOS Biology, was conducted in collaboration with researchers at the World Wildlife Fund.