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mrpg writes:

Conservation efforts and fishery management have allowed tuna and billfish to recover:

After decades of population declines, the future is looking brighter for several tuna and billfish species, such as southern bluefin tuna, black marlins and swordfish, thanks to years of successful fisheries management and conservation actions. But some sharks that live in these fishes' open water habitats are still in trouble, new research suggests.

These sharks, including oceanic whitetips and porbeagles, are often caught by accident within tuna and billfish fisheries. And a lack of dedicated management of these species has meant their chances of extinction continue to rise, researchers report in the Nov. 11 Science.

[...] The team found that the extinction risk for tunas and billfishes increased throughout the last half of the 20th century, with the trend reversing for tunas starting in the 1990s and billfishes in the 2010s. These shifts are tied to known reductions in fishing deaths for these species that occurred at the same time.

[...] But shark species are floundering in these very same waters where tuna and billfish are fished, where the sharks are often caught as bycatch.

[...] "While we are increasingly sustainably managing the commercially important, valuable target species of tunas and billfishes," says Juan-Jordá, "shark populations continue to decline, therefore, the risk of extinction has continued to increase."

Some solutions going forward, says Juan-Jordá, include catch limits for some species and establishing sustainability goals within tuna and billfish fisheries beyond just the targeted species, addressing the issue of sharks that are incidentally caught. And it's important to see if measures taken to reduce shark bycatch deaths are actually effective, she says.

"There is a clear need for significant improvement in shark-focused management, and organizations responsible for their management need to act quickly before it is too late," Simpfendorfer says.

Original Submission