Habitats must be protected to improve fisheries

New research published in Fish and Fisheries has found that protecting fish habitats is critical to recovering the world’s fisheries.  

The Griffith University-led study reviewed the habitat requirements for fish stocks across the globe. Nearly half of those reviewed were found to use habitats that are known to be in decline.  

“Our work is significant because overfishing is often pinned as the only cause of declines in the productivity of fisheries, which implies stricter fisheries regulations are the sole solution to overfishing. We found that nearly half of the world’s best researched fish stocks are using habitats that are in decline, like seagrass and mangroves,” said the study’s lead author Dr Chris Brown of Griffith’s Australian Rivers Institute.  

Many fish habitats are under-threat from human activities like coastal development, pollution and destructive fishing that not only catches fish, but also damages habitats on the ocean floor. Queensland for instance, has lost large areas of its seagrass meadows and mangrove forests to development of coastal infrastructure and pollution.  

The study looks at how protecting or restoring lost habitats can improve the status of fisheries, so that the fisheries can sustainably support higher catches.  

“Managing fish catch is an important part of ensuring we have sustainable fisheries that support food production and jobs. But we can’t just count on good fisheries management. Protecting the fish habitats we have left and restoring lost habitats like mangroves is crucial,” Dr Brown said.  

It has previously been estimated that 31% of fish stocks globally are over-exploited, meaning that catches could be higher if fishing pressure was reduced. But these previous estimates ignored the effects of habitat loss on the productivity of fisheries.  

“We analysed habitat use for 418 of the best researched fish stocks. These are stocks for which detailed monitoring data are available. They are commonly used to estimate how sustainable fish are at the global scale,” Dr Brown said.  

“We need to look beyond fisheries to other activities that are degrading habitats, like pollution that comes from on land, and coastal development.”

“Restoration of critical fish habitats such as mangroves, seagrass, and floodplains will increase the resilience of fish populations against overfishing. For example, in the Wet Tropics, northern Australia, reconnecting coastal lagoons with mangroves and the Great Barrier Reef has been the primary objective of many restoration projects for fish species such as barramundi to have a better chance of growing and reproducing” said study co-author Dr Fernanda Adame.  

“Managing fish habitats can be hard – we need to coordinate our management across the land and sea and across different industries, like infrastructure development and fisheries. But doing so is crucial to supporting the jobs created by fisheries and the opportunity to fish recreationally that is enjoyed by millions of Australians.” 

 The study was led by researchers from Griffith University with a partner at the University of Washington. The study was supported by funding from the Australian Research Council and the Richard C. and Lois M. Worthington Endowed Professorship in Fisheries Management. 

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