AFSC/NMML/CCEP: Characterizing and quantifying California sea lion and Pacific harbor seal use of offshore oil and gas platforms in California, 2013-2015

California sea lions (Zalophus californianus) and Pacific harbor seals (Phoca vitulina) use offshore oil and gas platforms as resting and foraging areas. Both species are protected by the Marine Mammal Protection Act (1972). The Bureau of Ocean Energy Management (BOEM) is required to collect information from platforms being used by California sea lions and harbor seals (or other pinniped species) with the goal of meeting environmental review and permitting requirements associated with the eventual decommissioning of offshore platforms. Decommissioning requirements are under the jurisdiction of BOEMs sister agency, the Bureau of Safety and Environmental Enforcement (BSEE). However, BOEM provides environmental studies and environmental review support for BSEE actions. To accomplish this goal, BOEM entered an inter-agency agreement with the National Marine Mammal Laboratories' California Current Ecosystem Program (CCEP; AFSC/NOAA) in 2012. Specifically, BOEM funded CCEP to conduct a study (from January 2012 to January 2015) to characterize and quantify California sea lion and Pacific harbor seal use of the platforms, including; abundance, seasonal use patterns, and age and sex class composition of animals on the platforms. Inter- (i.e. spatial) and intra- (i.e. temporal) platform comparisons were examined.