Shark populations are rebounding in the northwest Atlantic

In recent years, shark and ray populations have been increasingly threatened due to overfishing and other human activities. Over the past half a century, oceanic populations have decreased by a staggering 71 percent and one third of all sharks and rays are currently threatened with extinction. However, according to a new study led by Simon Fraser University (SFU), better fisheries management and conservation can be highly effective in reversing these worrisome trends.

By analyzing trends in fishing pressure, fisheries management, and population status for all wide-ranging coastal shark and ray species living in the western Atlantic Ocean, the experts found that populations in the northwest Atlantic recovered significantly following the implementation of a U.S. fishery management plan in 1993. This recovery – achieved by comprehensive regulation, monitoring, and enforcement – has halted the decline of three species and six out of eleven species are clearly rebuilding at the moment.

For these species, a strong system of regulations had been put in place, including catch reporting requirements, aggregate- and species-specific quotas, and catch prohibitions for several species. These regulations are enforced by the U.S. Coast Guard and law enforcement agencies, and the government continues to closely monitor and assess fisheries, while adding new regulations when needed.

“Our findings provide hope, but are a microcosm of the wider problem faced by sharks and rays,” said study lead author Nathan Pacoureau, a postdoctoral research fellow in Ecology and Conservation at SFU. “Many shark and ray species range widely and successful conservation in one country can be undone by less regulated fishing areas outside those borders.”

However, the researchers emphasized that several populations of the same species had collapsed in the southwest Atlantic Ocean due to unrestrained fishing. Currently, the number of wide-ranging coastal species threatened with extinction is nearly four times lower in the northwest than in the southwest Atlantic. 

“These sensitive species have very slow life histories and are often collateral damage of sustainable target fisheries for more productive species,” said study senior author Nicholas Dulvy, an expert in Marine Biodiversity and Conservation at SFU.

These findings highlight the urgent need for well-enforced governance and science-based limits on fishing in order to prevent population declines and reduce extinction risks for a variety of shark and ray species.

The study is published in the journal Proceedings of the National Academy of Sciences.

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By Andrei Ionescu, Earth.com Staff Writer

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