Pacific harbor seal (Phoca vitulina richardsi) monitoring at Point Reyes National Seashore and Golden Gate National Recreation Area: 2013 annual report
Codde S and Allen S. 2015. Pacific harbor seal (Phoca vitulina richardsi) monitoring at Point Reyes National Seashore and Golden Gate National Recreation Area: 2013 annual report. Natural Resource Report. NPS/SFAN/NRR—2015/919. National Park Service. Fort Collins, Colorado
Harbor seal surveys were conducted throughout the 2013 breeding and molting seasons (March-May and June-July, respectively) once to twice per week at the largest Point Reyes National Seashore and Golden Gate National Recreation Area harbor seal colonies, collectively referred to as Marin County locations. Members of the Harbor Seal Monitoring Volunteer Program assisted NPS staff in completing 260 surveys at eight Marin County locations, contributing an estimated 470 hours of monitoring. During the breeding season, peak counts of 2,656 adult and immature seals and 1,380 seal pups were recorded at all Marin County monitoring locations. Drakes Estero Complex had the most adult and immature seals (691), followed by Double Point (569). Drakes Estero Complex and Double Point accounted for 55% (764) of pups at Marin County haul-outs. During the molting season, a peak count of 4,288 animals was recorded at Marin County locations. During surveys, 109 disturbances to seals were recorded. The most frequent causes were unknown source (28%), humans on foot (17%), and birds (17%). Twelve regional surveys were conducted throughout the breeding and molting seasons at locations in Sonoma, Marin and San Mateo counties, and San Francisco Bay. Of these areas, Marin County locations accounted for 61% of breeding season adult and immature animals (2,577 of 4,196), 76% of pups (1,383 of 1,816), and 65% of seals during the molting season (4,303 of 6,599).
- Type
- Published Report
- Authors
- Codde, Sarah; Allen, Sarah
- Date of Issue
- 2015-02
- Publisher
- National Park Service
- Units
- GOGA , NRSS , PORE , SFAN
- Keywords
- Annual Report, Harbor Seals, Monitoring, Pinnipeds