Meteorological and geomorphological influence on harbor seal haul-out distribution behavior using drone imagery

Harbor seals in Kosterhavet National Park face critical challenges during summer months, as two sensitive life stages (pupping and molting) which are vital for the population’s success coincide in time with the increase in tourist activity. This study assessed how topography and meteorological conditions affect seal haul-out site use. Using drone surveys, high-resolution elevation models and slope maps were produced for major haul-out sites. Drone surveys from 2021 to 2023 provided seal counts during key life history stages—pupping and molting—with seal identified manually or using machine learning tools. Subsites within each skerry were defined based on repeated seal presence and classified depending on wind and wave exposure. Statistical analyses provided elevation and slope metrics on the locations seals choose to haul-out, allowing comparison between adults and pups across seasons revealing that pups consistently stay at lower elevations and flatter slopes than adults, with differences observed between adult distributions in pupping season versus other months. Initial linear models showed a preference for sheltered areas depending on wave exposition and for wind when the conditions became harsher. Generalized linear mixed-effects models were fitted showing a small positive influence by temperature and a minor negative effect caused by wind and waves in influencing the haul-out density. Harbor seals only a little part of the archipelago; therefore, it is necessary to prioritize frequently used haul-out sites during pupping and molting when building conservation plans. Strategically establishing seal sanctuaries could greatly improve the species' long-term resilience in the area. As the seal population is recovering from historical lows because of overhunting, it is vital to continue long-term monitoring. Future studies should address seasonal variability and the potential impacts of human activities such as boat traffic. Incorporating these factors into conservation planning will help ensure that harbor seals remain a stable component of the park’s ecosystem.

Author dc:creator

• Sebastián Isaac Enault de Cambra 1999-

Contributors dc:contributor

• Landbúnaðarháskóli Íslands

• Umhverfisbreytingar á norðurslóðum
• Harbor seals
• Phocids
• Marine mammals
• Drone surveys
• EnChiL
• UAV
• Topography
• Haulout behavior
• Climate
• Environmental monitoring
• Meteorology

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/1946/51405

OAI identifier oai:identifier

oai:skemman.is:1946/51405