Nearly half of the fish caught worldwide are from stocks that are scientifically monitored and, on average, are increasing in abundance. Effective management appears to be the main reason these stocks are at sustainable levels or successfully rebuilding.
That is the main finding of an international project led by the University of Washington to compile and analyze data from fisheries around the world. The results were published Jan. 13 in the Proceedings of the National Academy of Sciences.
"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 UW 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 -- or distinct populations of fish -- 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% 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. Now about 880 fish stocks are 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% to 40% of the world's fish catch that is 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 standardized 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 incentivize 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."
Other co-authors are from University of Victoria, University of Cape Town, National Institute of Fisheries Research (Morocco), Rutgers University, Seikai National Fisheries Research Institute Japan, CSIRO Oceans and Atmosphere, Fisheries New Zealand, Wildlife Conservation Society, Marine and Freshwater Research Center (Argentina), European Commission, Galway-Mayo Institute of Technology, Center for the Study of Marine Systems, Sustainable Fisheries Partnership, The Nature Conservancy, and the Food and Agriculture Organization of the United Nations.
Hilborn and collaborators recently presented this work at the Food and Agriculture Organization of the United Nations' International Symposium on Fisheries Sustainability in Rome.
The research was funded by the Science for Nature and People Partnership, a collaboration between the National Center for Ecological Analysis and Synthesis at UC Santa Barbara, The Nature Conservancy and Wildlife Conservation Society. Individual authors received funding from The Nature Conservancy, The Wildlife Conservation Society, the Walton Family Foundation, Environmental Defense Fund, the Richard C. and Lois M. Worthington Endowed Professorship in Fisheries Management and donations from 12 fishing companies.
More information is available at Sustainable Fisheries UW, an effort to communicate the science, policies and human dimensions of sustainable fisheries.
Proceedings of the National Academy of Sciences