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Keeping hammerheads alive

Posted by Michelle Heupel | Queensland, Australia

Hammerhead sharks are one of the most recognizable and iconic shark species. They are known to aggregate in areas like the Sea of Cortez and Galapagos Islands, but also travel large distances across the open ocean. These movement patterns expose hammerheads to a variety of threats in our oceans as they swim through areas where many fishing fleets operate. The unique hammer shape of their head means these sharks are easily and regularly captured in nets in coastal waters and they are also caught in longline fisheries in the open oceans. Hammerhead populations are dwindling and there is widespread global concern for these species as evidenced by their recent protection under the Convention on International Trade in Endangered Species and the Convention on Migratory Species. Unfortunately, our understanding of hammerhead sharks is still somewhat limited. It is apparent (although not well documented) that they often do not survive capture and handling in fisheries. Therefore, even if we release captured hammerhead sharks in an attempt to conserve the species, released individuals often still die. Research is needed to understand what makes hammerhead sharks so susceptible to capture stress and death. This knowledge can be used to develop best practice handling guidelines for incidentally captured hammerhead sharks to improve their survival after release and ensure conservation measures are having the desired effect — to keep hammerheads alive. The knowledge and guidelines created from this research should be communicated to fishers, fishery managers and conservation advocates around the globe to help save these amazing animals.