When a predator eats all or part of a fish that has already been hooked, experts refer to this as “depredation.” A new analysis by North Carolina Sea Grant now reveals the varying ways anglers experience this problem along the US East Coast: sharks are the primary culprits in the south, while seals predominate in the north.
We have already covered in detail why NOAA is developing a dedicated research strategy for this issue, as well as the potential roles of population trends, learned behavior, and technical deterrents. The new study addresses a different question: which species are taking the catch in which regions—and how do frequent losses alter anglers’ attitudes and decisions?
954 affected individuals, but not a representative sample of all anglers
Between July and October 2024, researchers surveyed recreational anglers from North Carolina to Maine via social media. Participation was open to individuals who had personally experienced depredation within the previous year. A total of 954 responses were analyzed. Respondents described factors such as target species, fishing locations, frequency, suspected predators, and their reactions to the losses.
This selection is crucial for interpreting the results. The study measures experiences within a group that has already been affected; it does not indicate what proportion of all anglers on the US East Coast experience depredation. Furthermore, the reported loss rates are based on the respondents’ estimates and recollections rather than on independently observed fishing trips.
Almost one in five catches affected—according to respondents’ estimates
Across all three study regions, participants estimated that nearly 20 percent of their catches were attacked by a predator. 62 percent identified sharks as the most frequent culprits, while 29 percent cited seals. The team also recorded predatory fish and birds, though these were mentioned far less frequently overall.
However, a single average figure masks the most important finding of the study published in Fisheries Research: latitude, fishing area, and target species influenced experiences more significantly than the broad category of “depredation” (loss of catch to predators).
In the South: Sharks in offshore fisheries
The southern region included Maryland, Virginia, and North Carolina. There, 95 percent of respondents identified sharks as the primary predators of their catch. On average, they estimated losing nearly 35 percent of hooked fish to sharks.
Many of these anglers fished further offshore and more frequently targeted tuna. This fundamentally distinguishes their situation from nearshore fisheries in the North. The survey did not identify any single shark species as the primary culprit; consequently, the high figures do not allow for conclusions regarding a specific species or the size of a population.
In the North: Seals more common, lower loss rate
The northern group comprised Maine, New Hampshire, Massachusetts, and Rhode Island. Here, 70 percent of participants identified seals as the most frequent predators of their catch. The estimated average loss rate due to seals—nine percent—was significantly lower than the figure for sharks in the south.
In the north, the focus was primarily on nearshore species such as striped bass. Consequently, the dynamics of conflict involving predators, habitat, and targeted fisheries differed from those of the southern tuna fishery. For the central region—New York and New Jersey—the picture was mixed, with comparatively low median values for both sharks and seals.
Frequent losses fuel opposition
The more frequently respondents experienced catch depredation, the more likely they were to support reducing or even eliminating the responsible predator population. This does not mean that all anglers called for such measures. However, the statistical relationship demonstrates how repeated losses can undermine acceptance of protected or recovering predator species.
Emotional reactions also depended on the region and the predator involved. In the north, seals triggered feelings of anger, sadness, and distress more frequently than sharks did. Encounters with sharks in that region were also associated—relatively more often—with astonishment and excitement. In the south, however, where reported losses to sharks were significantly higher, negative reactions to sharks were most intense.
Anglers don’t quit; they avoid certain areas
Despite their frustration, the respondents generally did not want to fish less. However, they reported avoiding areas where catch depredation occurred repeatedly. Consequently, the conflict can alter the spatial distribution of fishing effort without necessarily reducing the number of days spent fishing. This means the burden can shift to other areas or target species.
No one-size-fits-all solution for sharks and seals
The results argue against a single measure for the entire East Coast. A strategy addressing sharks in offshore tuna fisheries must take into account different animals, gear, and signals than an approach targeting seals in nearshore striped bass fisheries. Management strategies should therefore consider species (or predator groups), region, fishing method, and actual loss frequency in tandem.
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More InformationThe social dimension is equally important. Focusing solely on the weight of lost fish may lead to a delayed realization that frustration, area avoidance, and demands for population culling are on the rise. Practical solutions must limit actual losses while simultaneously preventing an entire group of predators from being labeled a problem in the absence of adequate population data.
What the survey leaves unanswered
The study provides a detailed picture of perceptions but not a direct ecological assessment. Self-reports can overestimate or underestimate actual losses, and the broad category of “sharks” does not allow for identification of specific species. Furthermore, because only anglers who had already been affected were permitted to participate, the sample cannot be extrapolated to determine the general prevalence of the problem.
It is precisely these limitations that make the study useful for management purposes: it highlights which questions now need to be examined using observer data, electronic documentation, and regional field studies. Depredation is not a uniform biological event, but rather a conflict—varying by region—between predators, fishers, and human expectations.