Pinniped Monitoring Data Summaries for the San Francisco Bay Area Inventory and Monitoring Network: 1983-2025 – Data Package

McMahon L , Sherrill K , Codde S . 2026. Pinniped Monitoring Data Summaries for the San Francisco Bay Area Inventory and Monitoring Network: 1983-2025 – Data Package. National Park Service. Fort Collins CO https://doi.org/10.57830/2316609

San Francisco Bay Area Network Inventory and Monitoring Network Pinniped Monitoring Data Summary Data Package. The summary data package was derived from the Native Survey Scale Pinnipeds Data Package datasets that have been summarized via R script, see xml metadata for further details. Pinniped Monitoring background: Within the order Carnivora, the Pinnipedia sub-order is a group of marine mammals that includes sea lions, fur seals, true seals, and walruses. Pinnipeds are keystone species who serve as excellent indicators of marine ecosystem health because they respond quickly to changing oceanic conditions. Conservation concerns include effects of climate change, human disturbance, oil spills, fishing activities (operational and biological), natural and anthropogenically enhanced toxic algal blooms, preservation of haul out habitats, biomagnified contaminants, and disease. Monitoring focuses on the two numerically dominant pinniped species that breed, haul out, and molt in San Francisco Bay Area Network (SFAN) parks: the Pacific Harbor Seal (Phoca vitulina richardii) and Northern Elephant Seal (Mirounga angustirostris). This information contributes significantly to the regional and stock-wide understanding of these species required under the Marine Mammal Protection Act of 1972. Ancillary data on other pinniped species are collected concurrently, but are not the primary targets of this monitoring protocol. Monitoring is performed annually at two SFAN parks: Point Reyes National Seashore (PORE) and Golden Gate National Recreation Area (GOGA). Objectives are to 1) determine the long-term trends in population size and seasonal distribution of seal populations at primary sites in the SFAN parks during the breeding and molt seasons, 2) determine long-term trends in reproductive success of seals through annual estimates of pup production at PORE and GOGA, and 3) determine the long-term trends in sources, frequency, and level of effects of natural and anthropogenic disturbances on harbor seal haul out use and productivity.

Type
Data Package
Authors
McMahon, Laura; Sherrill, Kirk; Codde, Sarah
Date of Issue
2026-07-08
Publisher
National Park Service
DOI
10.57830/2316609
Units
GOGA , PORE
Keywords
Bolinas Lagoon, California, Disturbance events, Double Point, Drakes Estero, Duxbury Reef, Elephant Seal, GOGA, Golden Gate National Recreation Area, Harbor Seal, Mammals, Marine Mammals, Mirounga angustirostris, Monitoring, Phoca vitulina, Pinniped Data Package, Pinnipeds, Point Bonita, Point Reyes, Point Reyes National Seashore, PORE, Protocol, Resight, Survey, Tomales Bay, Tomales Point, Wildlife
License
Public Domain

See also

Browse the catalog