Saving Sharks with Satellites

To study their movements in relation to marine protected areas, satellite tags were affixed to the dorsal fins (left) of great hammerhead sharks, Sphyrna mokarran (top right), tiger sharks Galeocerdo cuvier (bottom right) Credit: Dorsal fin - Frank Gibson Credit: Hammerhead and Tiger shark – Neil Hammerschlag, Ph.D.

In the past I have blogged about how the use of electronic tagging and tracking can support the conservation of marine animals. I have also addressed some misconceptions about shark tagging studies and discussed the value of such research for conservation management. Building off these topics, I would like to share the results of two newly published studies that use satellite tracking of sharks in which the data generated as important conservation implications.

To study their movements in relation to marine protected areas, satellite tags were affixed to the dorsal fins (left) of great hammerhead sharks, Sphyrna mokarran (top right), tiger sharks Galeocerdo cuvier (bottom right); Credit: Dorsal fin – Frank Gibson; Credit: Hammerhead and Tiger shark – Neil Hammerschlag, Ph.D.

The first study example, published in the Proceedings of the National Academy of Sciences tracked more than 100 sharks equipped with satellite tags from six different species in the North Atlantic while concurrently tracking 186 GPS-equipped longline fishing vessels. The results showed that commercial fishing vessels target shark hotspots, areas where sharks tend to congregate, in the North Atlantic. The researchers suggest that sharks are at risk of being overfished in these oceanic hotspots.

About 80 percent of the range for two of the most heavily fished species tracked—the blue and mako sharks—overlapped with the fishing vessels’ range. The study concluded that because current hotspots of shark activity are at particularly high risk of overfishing, the introduction of conservation measures such as catch quotas, size limits or marine protected areas will be necessary to protect oceanic sharks that are commercially important.

Source

The second study example, published in the journal Diversity and Distributions determined the core home range of 86 bull, great hammerhead and tiger sharks equipped with satellite tags in waters off south Florida and the northern —> Read More

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