Patterns of space use in sympatric marine colonial predators reveal scales of spatial partitioning

• Published in: Marine Ecology Progress Series
• Main Authors: Jones, Esther L., Mcconnell, Bernie J., Smout, Sophie, Hammond, Philip S., Duck, Callan, Morrison, Christopher D., Thompson, David, Russell, Deborah J. F., Vincent, Cécile, Cronin, Michelle, Sharples, Ruth J., Matthiopoulos, Jason
• Other Authors: Sea Mammal Research Unit, University of St Andrews Scotland, Centre for Research into Ecological and Environmental Modelling, Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Coastal & Marine Research Centre, University College Cork (UCC), Institute of Marine and Antarctic Studies, University of Tasmania Hobart, Australia (UTAS), Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: Halichoerus grypus; Phoca vitulina; Density estimation; Propagating uncertainty; Species distribution; Telemetry; Area-based conservation; [SDE]Environmental Sciences
• Online Access: https://hal.science/hal-01336579; https://doi.org/10.3354/meps11370

International audience Species distribution maps can provide important information to focus conservation efforts and enable spatial management of human activities. Two sympatric marine predators, grey seals Halichoerus grypus and harbour seals Phoca vitulina, have overlapping ranges on land and at sea but contrasting population dynamics around Britain: whilst grey seals have generally increased, harbour seals have shown significant regional declines. We analysed 2 decades of at-sea movement data and terrestrial count data from these species to produce high resolution, broad-scale maps of distribution and associated uncertainty to inform conservation and management. Our results showed that grey seals use offshore areas connected to their haul-out sites by prominent corridors, and harbour seals primarily stay within 50 km of the coastline. Both species show fine-scale offshore spatial segregation off the east coast of Britain and broad-scale partitioning off western Scotland. These results illustrate that, for broad-scale marine spatial planning, the conservation needs of harbour seals (primarily inshore, the exception being selected offshore usage areas) are different from those of grey seals (up to 100 km offshore and corridors connecting these areas to haul-out sites). More generally, our results illustrate the importance of detailed knowledge of marine predator distributions to inform marine spatial planning; for instance, spatial prioritisation is not necessarily the most effective spatial planning strategy even when conserving species with similar taxonomy.