spatial variation in foraging behaviour of a marine top predator (phoca vitulina) determined by a large-scale satellite tagging program海洋顶级食肉动物的觅食行为的空间变化(phoca vitulina)由一个大型卫星标签计划.pdf

Spatial Variation in Foraging Behaviour of a Marine Top Predator (Phoca vitulina) Determined by a Large-Scale Satellite Tagging Program 1,2 1 3 1 Ruth J. Sharples *, Simon E. Moss , Toby A. Patterson , Philip S. Hammond 1 Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, Scotland, United Kingdom, 2 The Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia, 3 CSIRO Wealth from Oceans Research Flagship, Hobart, Australia Abstract The harbour seal (Phoca vitulina) is a widespread marine predator in Northern Hemisphere waters. British populations have been subject to rapid declines in recent years. Food supply or inter-specific competition may be implicated but basic ecological data are lacking and there are few studies of harbour seal foraging distribution and habits. In this study, satellite tagging conducted at the major seal haul outs around the British Isles showed both that seal movements were highly variable among individuals and that foraging strategy appears to be specialized within particular regions. We investigated whether these apparent differences could be explained by individual level factors: by modelling measures of trip duration and distance travelled as a function of size, sex and body condition. However, these were not found to be good predictors of foraging trip duration or distance, which instead was best predicted by tagging region, time of year and inter-trip duration. Therefore, we propose that local habitat conditions and the constraints they impose are the major