Keeping fisheries sustainable

To identify the combinations of measures most consistently effective at reducing overfishing and rebuilding depleted stocks, the researchers collated the range of actions implemented for 288 studied stocks in 17 regions worldwide, accounting for 30% of all global marine catch from 1970 to 2017.

They examined how various measures impacted each stock, such as rebuilding plans, fleet-wide catch limits and individual quotas, the declaration of exclusive economic zones, and the ratification of international fishing treaties and fishery legislation. 

Rebuilding plans, which include fishing suspensions and reductions in allowable catches for depleted stocks, rapidly lowered fishing pressure and were found to be the most important factor for facilitating the recovery of overfished populations. The ratification of international fishing agreements and harvest control rules were the next most significant individual measures that helped reduce overfishing and rebuild biomass. 

The evaluation also demonstrated that the benefits of management actions are cumulative, says Michael Melnychuk, study co-author and research scientist at the University of Washington, in the US. “The more management tools that are put in place, the more likely that abundances of fish populations will remain at sustainability-based targets.” As every fishery is unique, he recommends using a variety of tools to provide safeguards, and create a more robust management system overall.

The regions included in the analysis generally have high management capacity compared with others around the world. Consequently, the findings are less suitable for countries that lack strong management capacity, says Manal Nader, director of the Institute of the Environment at the University of Balamand, Lebanon, who was not involved in the analysis.

Nader suggests the analysis did not encompass the diversity of problems facing the fisheries sector today, which in the Middle East and North Africa range from pollution and the destruction of nursery and spawning grounds, to the impacts of climate change on stocks and invasive species. He recommends a multi-dimensional economic, social and environmental approach to fisheries. “Regulation alone cannot reduce fishing pressure.”

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