The report, led by the University of Washington, concludes that “effective management appears to be the main reason these stocks are at sustainable levels or successfully rebuilding.”
The conclusion, which was published this week in the US Proceedings of the National Academy of Sciences, follows an international project to compile and analyse data from fisheries around the world.
"There is a narrative that fish stocks are declining around the world, that fisheries management is failing and we need new solutions – and it's totally wrong," said lead author Ray Hilborn, a professor in the University of Washington's School of Aquatic and Fishery Sciences. "Fish stocks are not all declining around the world. They are increasing in many places, and we already know how to solve problems through effective fisheries management."
The project builds on a decade-long international collaboration to assemble estimates of the status of fish stocks around the world. This information helps scientists and managers know where overfishing is occurring, or where some areas could support even more fishing. Now the team's database includes information on nearly half of the world's fish catch, up from about 20 percent represented in the last compilation in 2009.
"The key is, we want to know how well we are doing, where we need to improve, and what the problems are," Hilborn said. "Given that most countries are trying to provide long-term sustainable yield of their fisheries, we want to know where we are overfishing, and where there is potential for more yield in places we're not fully exploiting."
Over the past decade, the research team built a network of collaborators in countries and regions throughout the world, inputting their data on valuable fish populations in places such as the Mediterranean, Peru, Chile, Russia, Japan and northwest Africa. About 880 fish stocks are now included in the database, giving a much more comprehensive picture worldwide of the health and status of fish populations.
Still, most of the fish stocks in South Asia and Southeast Asia do not have scientific estimates of health and status available. Fisheries in India, Indonesia and China alone represent 30-40 percent of the world's fish catch that is, according to the authors “essentially unassessed”.
"There are still big gaps in the data and these gaps are more difficult to fill," said co-author Ana Parma, a principal scientist at Argentina's National Scientific and Technical Research Council and a member of The Nature Conservancy global board. "This is because the available information on smaller fisheries is more scattered, has not been standardised and is harder to collate, or because fisheries in many regions are not regularly monitored."
The researchers paired information about fish stocks with recently published data on fisheries management activities in about 30 countries. This analysis found that more intense management led to healthy or improving fish stocks, while little to no management led to overfishing and poor stock status.
These results show that fisheries management works when applied, and the solution for sustaining fisheries around the world is implementing effective fisheries management, the authors explained.
"With the data we were able to assemble, we could test whether fisheries management allows stocks to recover. We found that, emphatically, the answer is yes," said co-author Christopher Costello, a professor of environmental and resource economics at University of California, Santa Barbara, and a board member with Environmental Defense Fund. "This really gives credibility to the fishery managers and governments around the world that are willing to take strong actions."
Fisheries management should be tailored to fit the characteristics of the different fisheries and the needs of specific countries and regions for it to be successful. Approaches that have been effective in many large-scale industrial fisheries in developed countries cannot be expected to work for small-scale fisheries, especially in regions with limited economic and technical resources and weak governance systems, Parma said.
The main goal should be to reduce the total fishing pressure when it is too high, and find ways to incentivise fishing fleets to value healthy fish stocks.
"There isn't really a one-size-fits-all management approach," Costello said. "We need to design the way we manage fisheries so that fishermen around the world have a long-term stake in the health of the ocean."
