2018 Harbor Seal Pupping Season Winding Down in Marin County

Several harbor seals hauled out on a rock at Point Bonita
Harbor seals at Point Bonita in mid-June. Normally only a handful of pups are recorded at this site, and this year was no different.

NPS / Maritte O'Gallagher

June 2018 - Right on schedule, the first harbor seal pups of the 2018 breeding season were recorded at Drakes Estero and Tomales Bay on March 23. The season peaked in late April and early May, with a maximum number of approximately 1,000 pups recorded throughout Marin County locations. This number is similar to the 16-year average of 1,080 pups. Drakes Estero and Bolinas Lagoon were the two top sites with approximately 360 and 260 pups, respectively. Bolinas Lagoon has had increased pup counts over the last six years and numbers are now about 60% higher than the site’s average.

The number of surveys at Double Point has been reduced due to safety concerns at the observation spot. Surveys are now concentrated during the peak of pupping, and numbers have been low for a second year in a row. This year’s peak of 150 pups is about 50% less than the site’s average. It is unknown what is causing this decline but possibilities include an increase in coyotes and the effects large 2017 storms on the beach habitat. Please check out the latest seasonal update or email Sarah Codde for more information.

Last updated: June 29, 2018