In a world’s-first study of the global state of coral reef fisheries, a team of researchers estimates that about half of the world’s reefs failed at least one of two key sustainability tests: either their fish stocks are depleted to dangerously low levels, or ongoing fishing pressure exceeds the fish stocks’ capacity to recover.
A worldwide fishing crisis in the late 20th century made headlines as commercial stocks of Peruvian anchovies, Atlantic and Scandinavian herring and Northern cod plummeted. But by preventing overfishing, effective, science-based management improved stocks dramatically. However, fishing for a single species is much less common on coral reefs, where fishers often use methods that target large numbers of species whose biology is very different and often poorly characterized. For such “multi-species fisheries”, it has always been challenging to determine if overfishing is taking place. The new study offers an innovative way forward.
“Despite the alarming state of multi-species reef fisheries as a whole, we believe that our findings can help us to shape a more sustainable future,” said Sean Connolly, co-author of the study and staff scientist at the Smithsonian Tropical Research Institute (STRI) in Panama. “Also, the analytical approach that we developed provides a foundation for smart management strategies to promote sustainable yield of multi-species fisheries—even at poorly studied sites.”
“Coral reef fisheries are worth billions of US dollars worldwide. In the Global South, they support the livelihoods and provide vital nutrients to tens of millions of people,” adds Joshua Cinner, a Distinguished Professor at James Cook University and study co-author. “So tackling this problem is crucial for the health and livelihoods of people in some of the most vulnerable regions of the world.”
An international team used fish biomass data from more than 2000 different reefs to calculate what they term “context-specific” sustainability reference points. “While assessing fish abundances in a particular location is straightforward, assessing sustainability requires knowing how much fish that location could support if we were not fishing, and also how productive those fish assemblages are – how fast they can replenish their stocks after depletion by fishing,” explains lead-author, Jessica Zamborain-Mason from the Harvard T.H. Chan School of Public Heath. “To get a handle on these numbers, we asked how fish communities recover when they are in no-take areas and how many fish there are in remote locations far from direct human impacts. Additionally, what a location can support varies naturally due to things like temperature, productivity, and the amount of healthy coral, which we also took into account in the analysis.”
According to Zamborain-Mason, these estimates can provide a starting point for sustainable management in places where local data is limited, or where there are critical gaps, by leveraging what we know about similar locations where more information is available.
In a press release from the Leibniz Centre for Tropical Marine Research, co-author Sebastian Ferse says: “There is no need to ban fishing on reefs to save an ecosystem. Our models show that simply improving fisheries management by reducing fishing to 80 percent of the maximum possible yield is enough to increase stocks and biodiversity. This model makes it possible to develop tailor-made management approaches that take both fisheries and conservation goals into account.” Authors of this study are affiliated with the Harvard T.H. Chan School of Public Health; James Cook University; Dalhousie University; Lancaster University; University of Leeds; University of Queensland; University of California, Santa Barbara; University of Technology, Sydney; University of Tasmania; MRAG Ltd.; Leibniz Centre for Tropical Marine Research (ZMT); University of Bremen; National Geographic Society, Pristine Seas Program; Hawai‘i Institute of Marine Biology, Blue Ventures; King Abdullah University of Science and Technology; University of Montpellier, CNRS; Newcastle University; University of New Caledonia, NOAA Pacific Islands Fisheries Science Center; University of Western Australia, and the Smithsonian Tropical Research Institute.
STRI, headquartered in Panama City, Panama, is a unit of the Smithsonian. The institute furthers the understanding of tropical biodiversity and its importance to human welfare, trains students to conduct research in the tropics and promotes conservation by increasing public awareness of the beauty and importance of tropical ecosystems. Watch STRI’s video and visit the institute on its website and on Facebook, Twitter and Instagram for updates.
Ref: Zamborain-Mason, J, Cinner, JE, McNeil, MA et al. 2023. Sustainable reference points for multispecies coral reef fisheries. Nature. https://www.nature.com/articles/s41467-023-41040-z