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California Current Marine Mammal Assessment Program

We assess the population status of marine mammals in the California Current.


The California Current Marine Mammal Assessment Program conducts research on population assessment for species inhabiting waters off the U.S. West Coast, and on improving assessment methodology for application throughout the U.S. and internationally. We provide scientific advice to regional and national policy-makers within NOAA, pursuant to the Marine Mammal Protection Act and Endangered Species Act.  

Research Areas

Annual Stock Assessment Reports for Pacific Marine Mammals

Our program is responsible for producing annual stock assessments for marine mammal populations inhabiting waters off the U.S. West Coast.

Population Surveys

Our program conducts ship-, aerial-, and land-based surveys of marine mammals throughout the California Current large marine ecosystem. Large-vessel line-transect cetacean surveys have been conducted since 1991, with recent surveys supported through the PacMAPPS Initiative. Aerial surveys are conducted for harbor porpoises and pinnipeds. Shore-based surveys are conducted for gray whales, led by the Cetacean Health and Life History Program.

Estimating Population Parameters

Our program applies or develops novel analytical methods for estimating population parameters such as population size, population trends, and survival rates from line-transect, passive acoustic, and photo ID data collected from our and others’ surveys.

Estimating Fisheries Bycatch and Other Sources of Human-caused Mortality

We use fishery observer data to provide annual estimates of marine mammal bycatch in fisheries along the U.S. West Coast, and to identify environmental factors and fishing gear improvements to reduce bycatch risk. We work with the Pacific Offshore Take Reduction Team that includes fishermen, conservation organizations, and scientists, to evaluate bycatch trends in the U.S. West Coast swordfish gillnet fishery and implement strategies for bycatch reduction. Our involvement in bycatch reduction and assessment led to the introduction of acoustic pingers into the swordfish gillnet fishery in the 1990s, which resulted in the elimination of beaked whale bycatch and large reductions in the bycatch of other marine mammal species.

Passive Acoustics

Sound travels exceptionally well in the marine environment, and marine mammals have evolved to use sound as their primary mode of interacting with the environment. By passively monitoring the ocean using acoustic sensors, our scientists study marine mammals and human-caused noise, as well as the impact of noise on the marine environment. 

Population Risk Assessment

Risk refers to the likelihood and severity of negative outcomes (e.g., of an endangered population not recovering). Our scientists conducts analyses to evaluate risks to marine mammal associated with human stressors or environmental change (e.g., entanglement risk for large whales). They communicate risk assessment findings to NOAA managers, and develop tools to help guide decisions for managing risk.

Modeling Cetacean Densities in Space and Time

Species distribution models or “habitat models” identify quantitative relationships between animal distributions and a variety of ecologically relevant habitat variables (e.g., sea surface temperature, oceanic fronts, seafloor depth). Our scientists develop species distribution models for cetaceans, based on the Marine Mammal and Turtle Division's extensive line-transect survey data collected in the Pacific Ocean since the mid-1980s. The resulting model predictions are used by scientists, managers and other federal agencies to assess and mitigate potential impacts to cetaceans from a wide range of human activities

Long-Term Dataset on California Sea Lion Diets

For more than 40 years, we have been collecting a quarterly time series of California sea lion diet at Channel Islands rookeries in the Southern California Bight. This time series has applications to forage fish stock assessment, ecosystem-based management, and improving our understanding of how pelagic forage in the California Current Ecosystem varies, drives predator population dynamics, and is shifting as our oceans warm.

Our Team 

Dr. Jeff Moore leads the California Current Marine Mammal Assessment Program.




Last updated by Southwest Fisheries Science Center on June 07, 2023