Harbour seal movement patterns

• Main Author: Thompson, Paul M
• Format: Book Part
• Language: English
• Published: Oxford University PressOxford 1993
• Subjects: harbour seal
• Online Access: http://dx.doi.org/10.1093/oso/9780198540694.003.0013; https://academic.oup.com/book/chapter-pdf/52430144/isbn-9780198540694-book-part-13.pdf

Abstract In many species of phocids, the capacity to store energy as blubber has led to a separation of feeding and breeding activity. Recent marking and telemetric studies have shown that harbour seals may travel extensively and that their breeding activity may also constrain foraging behaviour. This paper assesses the relative importance of variations in food availability, breeding activity and predation pressure in shaping movement patterns. Two broad categories of movements are recognized. The first is those between haul-out sites and the sea. These are primarily for foraging, and appear to occur within 50 km of haul-out sites. The duration, timing and locations of these trips are related to changes in environmental conditions and breeding activity. The second is movements which occur between different haul-out sites. These may involve dispersal, or they can occur seasonally, when seals switch to sites which are more suitable for pupping or are closer to foraging areas. Regional variations exist in the extent of seasonal movements, probably in relation to the relative distribution of foraging areas and suitable haul-out sites.