Image:

Seal equipped with tracking device

Photo courtesy of Gordon Hastie/Sea Mammal Research Unit

A groundbreaking study led by the University of St Andrews has produced the most detailed maps yet of grey and harbour seal locations across Northwest Europe, covering most seal populations in the continental shelf region.

Published on December 16th in the Journal of Applied Ecology, the research merged GPS tracking data from over 840 seals across seven European nations (UK, Ireland, France, Belgium, Netherlands, Germany, and Denmark) with information on seals resting onshore. This combination allowed scientists to build comprehensive at-sea density maps for both seal types.

Conducted by the Sea Mammal Research Unit (SMRU) with the collaboration of researchers from nine European institutions, the analysis revealed that seals frequently move across national maritime boundaries during foraging. These international movements are not always considered in environmental evaluations or protection policies.

Lead researcher Dr Matt Carter of SMRU explained: “Our goal was to provide tools for developers, conservationists, and scientists that could indicate how many seals might inhabit certain oceanic zones at any given time and where those animals may have originated.”

Since seals are a protected species in both the UK and EU, human activities at sea—like windfarm construction—must take potential effects on these animals and their protected habitats into account. However, existing wildlife maps often focus on individual nations and fail to incorporate how seals travel between regions.

Dr Carter further noted: “The recently developed maps, accessible to the public, allow users to view seal distributions specific to each country included in the project. In the UK, it’s now also possible to link seal densities at sea to regional entities, Seal Monitoring Units, and designated Special Areas of Conservation. This enhancement will help conservation efforts connect offshore developments to seal population trends noted on land. We discovered that disregarding cross-border movements may lead to underestimating seal numbers by as much as ten times in some territories.”

Dr Debbie Russell, also from SMRU and a co-leader on the study, emphasized: “This important resource captures data on more than one-third of the global grey seal population and most of Europe’s harbour seals. It owes its success to the extensive collaboration between seal-tracking researchers and the dedication of numerous individuals and organizations who have monitored seal populations along over 40,000 kilometers of coastline.”

Journal

Journal of Applied Ecology

DOI

10.1111/1365-2664.70236

Research Method

Meta-analysis

Focus of Study

Animals

Title of Paper

At-sea distribution of seals on the Northwest European Shelf: towards transboundary conservation and management

Date of Publication

16-Dec-2025