Sharks at Risk of Being Overfished in “Oceanic Hotspots”

Written by on February 3, 2016 in Marine Life, Sharks

A new study found that many commercial fishing vessels target shark hotspots (areas where sharks congregate) in the North Atlantic, putting sharks at risk of overfishing in these locations.

Shortfin mako shark.

Shortfin mako shark. Photo credit: Mark Conlin, NOAA.

Tens of millions of oceanic sharks are caught in commercial fisheries every year, but traditional management techniques, like catch shares or size limits, are not typically used. There’s also a lack of data on where and when sharks are most likely to encounter fishing vessels.

“Many studies have tracked sharks, and many studies have tracked fishing vessels, but fine-scale tracking of sharks and fishing vessels together is lacking, even though this should better inform how shark fisheries should be regulated,” David Sims, senior author of the study and professor at the Marine Biological Association, explained in a news release.

Using satellite tags, an international team of researchers tracked more than 100 sharks of six different species in the North Atlantic over a four year period. At the same time, they were tracking 186 Spanish and Portuguese longline fishing vessels. They found that the fishing vessels were often in the same location as the sharks.

A blue shark (Prionace glauca).

A blue shark (Prionace glauca) caught on skipjack bait. Photo credit: Apex Predators Program, NOAA/NEFSC.

About 80% of the range of blue and mako sharks (two of the most heavily fished species tracked in the study) overlapped with the range of the fishing vessels. The researchers estimate that blue sharks are vulnerable to capture 20 days of the month, while mako sharks are vulnerable 12 days of the month.

The findings suggest that catch quotas or size limits, which aren’t currently used, might be necessary to prevent population declines of commercially important species.

“Our research clearly demonstrates the importance of satellite tagging data for conservation,” said Neil Hammerschlag, director of the UM Shark Research and Conservation Program. “The findings both identify the problem as well as provide a path for protecting oceanic sharks.”

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Copyright © 2016 by Marine Science Today, a publication of Marine Science Today LLC.

About the Author

About the Author: Emily Tripp is the Publisher and Editor of She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science and a Master of Advanced Studies degree in Marine Biodiversity and Conservation from Scripps Institution of Oceanography. When she's not writing about marine science, she's probably running around outside or playing with her dog. .


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