doi.org
Horizontal movements and diving behaviour of two vagrant hooded seal (Cystophora cristata) pups following rehabilitation in Germany - Polar Biology
The hooded seal (Cystophora cristata) is an Arctic phocid seal occasionally observed far outside its native range, including the European Atlantic shelf seas. This study presents the movements and diving behaviour of two female hooded seal pups after rehabilitation and release in the German North Sea. We tracked the animals using satellite telemetry to evaluate post-release survival and movement behaviour. Within one month, one seal travelled through the North Sea to the coast of United Kingdom, and then further northward to the Norwegian west coast, suggesting a successful return to Arctic waters. In contrast, the second seal remained in the North Sea and exhibited shallower and shorter dives over time, with extensive surface resting. She was ultimately found in poor condition in the United Kingdom and placed in permanent captivity. These cases highlight the species’ high dispersal capacity, yet also underline the challenges vagrant individuals face in suboptimal non-native habitats. The contrasting outcomes suggest that rehabilitation and release of such Arctic vagrants should be assessed case-by-case, considering the animal’s age, health, and timing of the release in relation to the expected prey availability. This study emphasizes the importance of satellite telemetry in evaluating post-release success and contributes to the broader discussion on the viability and ethics of rehabilitating extralimital marine mammals.
