Most of us have been there. A tug at the line and suddenly...Fish On! Without warning, during the ensuing fight, the line suddenly goes slack, and the fish you were anticipating surfaces with only its head.
This interaction is known as depredation, defined as “the partial or complete removal of fish or fishing gear by a non-target species.” In the Gulf, depredation is a phenomenon that is becoming increasingly familiar to recreational and commercial fishers alike.
Who’s to blame? Hook-and-line fishers encounter depredation from a number of different species. Off the Texas coast, barracuda and greater amberjack are common depredators, while Florida fishers are experiencing increases in depredation from goliath grouper. In our neck of the woods (Mississippi and Alabama), depredation is most often caused by sharks.
Why is this happening? Many fishers claim that depredation events are increasing in frequency. If so, what’s causing this increase? At its core, depredation is a human-wildlife conflict over a shared resource. As more and more fishers head offshore to fish, they are encountering shark populations that are starting to recover following decades of overharvest.
Who’s impacted? The economic impacts of depredation can be substantial for both commercial and recreational sectors. For example, depredation by sperm whales costs the commercial fishery for sablefish and Patagonian toothfish more than $3 million per year! Similarly, depredation by sharks in the commercial shrimp fishery results in time lost as fishers must repair damaged nets and locate new areas to trawl. Recreational fishers who experience depredation are less likely to support conservation initiatives aimed at the culprit species, ultimately impacting recovery potential for these populations.
What can we do? Addressing increases in depredation will require both characterization and mitigation. First, the extent of depredation needs to be characterized. During what time of the year is depredation most severe? Which regions are most impacted? Which species are responsible? Once depredation has been accurately characterized, we can begin to develop strategies for mitigation. What techniques are currently used to avoid depredation? What technologies can we explore to mitigate depredation in the future?
What’s Sea Grant’s role? Sea Grant is playing an active role in both the characterization and mitigation of depredation. We’re currently planning and organizing workshops with commercial shrimp industry representatives to discuss the issue of shark depredation and share experiences and perspectives. In addition, we’re working to develop new shark deterrent devices that would reduce depredation in both commercial shrimp trawls and recreational hook-and-line fisheries. Ultimately, novel approaches and new collaborations are needed to ensure peaceful coexistence between hungry depredators and frustrated fishers.
Meet the author
(J.) Marcus Drymon, Ph.D.
Marine Fisheries Extension Lead
Marcus is a marine fisheries ecologist, and his research interests are in applied fisheries ecology. The bulk of his research has focused on coastal sharks. He works on many commercially and... Read more
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