FORT PIERCE, Fla. - Shark depredation is a hot-button issue in recreational fishing, as anglers face off against these stealthy ocean predators. Sharks sometimes snatch fish straight off the line, often leaving nothing but scraps – or a broken leader – as evidence of their heist.

The Southeast, a major hub for saltwater fishing, is a depredation “hot spot” due to high fishing activity. While fisheries managers in the United States monitor shark depredation in commercial fisheries, efforts to evaluate these interactions in recreational fishing have been limited.

With Florida’s recreational fishing being economically vital and concerns about rising shark depredation, understanding its extent is crucial. A major research gap is identifying depredating shark species, as most events occur at depth and are rarely observed, making accurate identification difficult.

Florida Atlantic University Harbor Branch Oceanographic Institute researchers and collaborators have addressed these challenges by involving the public in citizen-science research. Using multiple methodologies that included social media, online angler surveys, cooperative fishery-dependent charters and genetic analysis, the study uncovers the scope and impact of shark depredation in Florida’s recreational fisheries.

Bull, sandbar sharks found most depredating

Results of the study, published in the International Council for the Exploration of the Sea (ICES) Journal of Marine Science, reveal that across methodologies, snapper-grouper species were the most frequently depredated target species group, and bull sharks and sandbar sharks were the most commonly identified depredating species. Findings show 43% of anglers experienced depredation and the probability of experiencing depredation ranged from 10% to 60% and varied both regionally and seasonally.

“Our research provides crucial insights into the growing challenge of shark depredation, helping to build a comprehensive understanding of this human-wildlife conflict and how different fishery sectors are being affected by it,” said Matt Ajemian, Ph.D., senior author, an associate research professor and director of the Fisheries Ecology and Conservation Lab (FEC) at FAU Harbor Branch.

For the project, Ajemian and his team collaborated with the University of Massachusetts Dartmouth, Cramer Fish Sciences, Mississippi State University, Mississippi-Alabama Sea Grant Consortium and the Office of Sustainable Fisheries, National Marine Fisheries Service, from June 2020 to September 2023 to quantify frequency and impact and to analyze spatial and temporal trends.