NOAA’s Strategy for Understanding Shark Depredation

NOAA- Shark depredation, the removal or damage of fish by sharks, has become a growing issue with impacts ranging from economic losses from lost or damaged catch, bait, and gear to increased mortality of released fish and degraded fishing experiences. NOAA is developing a strategic plan on the issue of shark depredation. Reports of shark interactions have increased in recent years due to potentially learned behavior, rebuilding of some shark populations, increasing fishing effort, and more fish being released and discarded. However, shark depredation is not a recent phenomenon. To address the variety of theories on shark depredation, NOAA is using a multiple step approach to answer many of these questions. The framework that will come out of this strategic plan will continue to build on a strong state-federal partnership to give policymakers, stakeholders, and the public better information on how to best manage this issue.

Research Questions

Are there more sharks?

Current public perception suggests that the increase in depredation is a result of increased shark populations. While management has been successful in rebuilding some shark species (e.g., the Atlantic blacktip shark stock), other shark species have not recovered and need continued rebuilding (e.g., the dusky shark stock). Still other sharks have an unknown status. Two species in particular—sandbar shark and bull shark—have been implicated as the major depredation species in recreational fisheries targeting snapper and grouper in the Atlantic. In May 2026, NOAA Fisheries began the process of performing a stock assessment on sandbar shark, which was last assessed in 2018. Results of this assessment will be available in early 2027. This assessment will involve traditional approaches and test alternate approaches for determining if sandbar shark populations have increased. If the alternate approach is successful, a new assessment on bull shark, whose status is unknown, will begin in late 2027.

Have sharks learned to associate fishing activities with increased opportunities for feeding?

Emerging evidence indicates that individual sharks may learn from repeated encounters with fishing activity and associate the sound of vessel engines, the hauling of gear, or the discarding of undersized fish with feeding opportunities. Several areas have been identified as “high depredation risk areas” in the Gulf of America. Beginning this year, NOAA scientists will use these areas for experimental analysis in cooperation with commercial shark longliners. Teams will establish a listening station acoustic telemetry array at each site. Sharks captured in these areas will be tagged with acoustic pinger tags, which will follow their movements and residency for one year. Simultaneously, NOAA will monitor depredation rates at these sites in cooperation with for-hire and recreational anglers, who report their fishing activities and depredation rates. Lessons learned from these experiments will help determine if depredation is isolated to individual sharks or systematic across the population. These experiments in the southeast United States have the potential to be tested in other areas where depredation is an issue, such as the U.S. Pacific and Caribbean Islands.

Do deterrents reduce the level of shark depredation?

A variety of deterrents have been proposed to reduce shark depredation, including electromagnetic devices and various types of metals. While some studies have shown promise, deterrents may vary in their ability to repel different species of sharks and under different conditions. NOAA is currently conducting a meta-analysis with colleagues from state-agencies, private research institutions, and universities to evaluate broad scale effectiveness of deterrents. This work considers not only their ability to repel sharks, but also the costs of applying these deterrents. NOAA will also continue to invest in research to support the development and testing of deterrents.

How does management of shark populations impact shark depredation?

The number of active commercial shark fishermen has declined over the last decade, and most recreational anglers practice catch and release fishing for sharks. NOAA Fisheries is in the process of considering and implementing science-based regulatory adjustments in the Atlantic Ocean and Gulf of America that align shark catch limits with the latest stock assessments and increase operational flexibility for commercial and recreational stakeholders. For more information on the latest proposed and final rules, sign up to receive emails.

Shark Depredation Strategy Committee

Kelly Denit, Director of NOAA Fisheries Office of Sustainable Fisheries

Laura Grimm, NOAA Deputy Under Secretary for Oceans and Atmosphere

Dr. Evan Howell, NOAA Fisheries Deputy Assistant Administrator for Scientific Programs

Dr. John Carlson, Special Advisor for Shark Depredation to the Deputy Under Secretary for Oceans and Atmosphere

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Wayne Creed

Administrator

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