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Harbor seal behavioral response to boaters at Bair Island refuge

By Kathlyn Snyder Fox

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Harbor seals (Phoca Vitulina Richardsi) that haul out on the banks of Corkscrew Slough within Bair Island Refuge, San Mateo County, California encounter a variety of boats along the waterway. This study documented numbers of seals and boats using Corkscrew Slough and examined seals' behavioral responses to boats. Seal counts were also obtained at Outer Bair Island, where boats are rare.
Maximum counts of 50-60 seals were obtained during pupping-molting season. Seals and boaters were present year round, but seals encountered boats less than 1% of the time observed. Motorized boats represented 49% of traffic and non-motorized 40%. Non-motorized boats caused 55% of flush responses.
While seal vigilance increased as boats passed the haul out, seals relaxed within 10 minutes of boats' disappearance. On days with multiple boats, the number of seals was significantly fewer than on days with no boats. Seal vigilance increased as boats came closer to seals. 


Katie Carroll

Date 2008
Publisher San Jose State University ScholarWorks
Department Environmental Studies
Degree Master of Science
Language English
University San Jose State University
Cite this work

Researchers should cite this work as follows:

  1. Animal behavior
  2. Animal roles
  3. Animal welfare
  4. Conservation
  5. Ecology
  6. Environment
  7. Mammals
  8. Marine animals
  9. Marine mammals
  10. Nature
  11. Physical environment
  12. Seals
  13. Wild animals