Harbour seals (Phoca vitulina) basking on a rocky shore. Recent data shows these charismatic marine mammals have surged in the past few decades. However, new research suggests this increased population size remains compatible with sustainable fisheries.
Photo Credit: Jeremy Kiszka, Ph.D., Florida International University.
Scientific Frontline: "At a Glance" Summary
- Main Discovery: Anthropogenic fishing effort, driven by management decisions, serves as the primary determinant of fishery yields in the North Sea rather than predation pressure from recovering large marine mammal populations.
- Methodology: Researchers constructed a comprehensive ecosystem model of the southern North Sea and eastern English Channel, integrating data from 12 commercial fishing fleets and the complete marine food web, ranging from microscopic plankton to apex predators like gray seals and harbor porpoises.
- Key Data: The model synthesized extensive real-world datasets, including predator diet studies, fish stock assessments, and historical fisheries catch records, to accurately simulate the interplay between ecological dynamics and human harvest rates.
- Significance: This analysis demonstrates that the conservation of protected predator species is compatible with sustainable seafood production, challenging the prevailing assumption that recovering predator populations inevitably compromise commercial fishery viability.
- Future Application: Findings support the broader implementation of ecosystem-based fisheries management (EBFM) strategies that prioritize regulating human fishing pressure to balance economic objectives with ecological recovery.
- Branch of Science: Marine Ecology and Fisheries Management.
- Additional Detail: Published in the Canadian Journal of Fisheries and Aquatic Sciences, the study indicates that while total consumption by predators increased alongside their population growth, its impact on fish stocks remained subordinate to the volume of biomass removed by commercial fleets.
A new research study found that well-managed fisheries can support the recovery of large marine predators such as seals and porpoises, showing that conservation and sustainable seafood production can go hand in hand.
While the impacts of protected species are often debated, the study led by researchers at University of Miami Rosenstiel School of Marine, Atmospheric and Earth Science’s Cooperative Institute for Marine and Atmospheric Studies (CIMAS), showed that fishing effort—not predator recovery—is the main driver of fishery yields in the North Sea.
“Our findings offer an important takeaway: fisheries management goals can be achieved without sacrificing conservation goals,” said the study’s lead author Matthew Woodstock, an assistant scientist at CIMAS. “This new evidence can help reframe the conversation around how conservation and economic activity can coexist.”
To conduct the study, the researchers developed a comprehensive ecosystem model of the southern North Sea and eastern English Channel to capture the full marine food web—from microscopic plankton to top predators such as gray seals, harbor porpoises, and seabirds—alongside 12 commercial fishing fleets. The model was grounded in real-world data, drawing on diet studies, fish stock assessments, and fisheries catch records to reflect conditions as accurately as possible.
The analysis found that the recovery of large marine predators does not automatically lead to declines in fishery yields. Although seals and porpoises consumed more fish as their populations increased, these impacts were outweighed by the effects of fisheries management decisions. In these regions, the data suggest that sustainable fisheries and recovering predator populations can coexist when fishing effort is managed effectively.
This study adds new, data-driven insights from one of the world’s most heavily fished regions, showing that increasing seal populations in the southern North Sea have not curtailed fisheries operations.
The findings support ecosystem-based fisheries management—an approach that looks at the entire food web and environment—by demonstrating that predator consumption is often less impactful than human fishing pressure, helping managers balance conservation goals with sustainable seafood production and fishing livelihoods.
Published in journal: Canadian Journal of Fisheries and Aquatic Sciences
Authors: Matthew S. Woodstock, Jeremy J. Kiszka, Peter G.H. Evans, James J. Waggitt, and Yuying Zhang
Source/Credit: Rosenstiel School of Marine and Atmospheric Science | Annie Reisewitz
Reference Number: mb012326_01