Figure 1. Marine Mammal hotspots within the Monterey Bay, Gulf of the Farallones, and Cordell Bank National Marine Sanctuaries. [View Larger]
The region's marine mammal community is a mix of permanent and seasonal residents as well as species that use these waters for shorter periods - either as a feeding destination or in transit during long-distance migratory journeys (such as gray whales).
These waters are also important to several marine mammal species that are considered of special concern because of their reduced or declining populations. Examples include the humpback whale, blue whale, gray whale, northern fur seal and Steller sea lion.
InhabitantsFor more information on marine mammal populations specific to a particular sanctuary, please visit the individual pages for Cordell Bank, Gulf of the Farallones and Monterey Bay. Below are examples of the species found in the northern California region:
- Gray whale
- Humpback whale
- Blue whale
- Pacific white-sided dolphin
- Harbor porpoise
- Dall's porpoise
Humpback whale and Shearwaters at feeding frenzy
Risso's Dolphin Grampus griseus. This one was bow riding the wake of a blue whale Balaenoptera musculus, which was cruising at about 10 knots with an entourage of at least three dolphin species.
- California sea lion
- Northern fur seal
- Steller sea lion
- Northern elephant seal
- Harbor seal
- Southern sea otter
Conservation and Management IssuesHuman impacts to marine mammal populations worldwide include competition for food with commercial and recreational fisheries, entanglement in fishing gear and other marine debris, disturbance and injury from ocean noise, injury or death from ship strikes, and, in some cases, residual effects from past harvesting or bycatch.
In addition to human impacts, changes in climate and oceanographic conditions affect marine mammals. The prevalence of these animals in sanctuary waters changes from year to year due to fluctuations in marine conditions such as El Niño.
MonitoringMarine mammal-focused monitoring efforts in the northern California region are numerous and range from regional, multi-agency studies to more focused efforts. For a full list of each sanctuary's monitoring efforts, see the individual monitoring sections for the Cordell Bank, Gulf of the Farallones and Monterey Bay sanctuaries. A sample of research efforts is provided below.
The three sanctuaries are all participating in two studies whose geographic range reaches well beyond the sanctuaries' own boundaries:
- Collaborative Survey of Cetacean Abundance and the Pelagic Ecosystem (CSCAPE) is a joint effort between the National Oceanic and Atmospheric Administration (NOAA) Fisheries and the National Marine Sanctuary Program to assess the abundance and distribution of marine mammals and characterize the pelagic ecosystem off the U.S. West Coast.
- Tagging of Pacific Pelagics (TOPP) , a pilot program of the Census of Marine Life, is part of an international endeavor to determine what lives in the world's ocean. TOPP scientists explore the Pacific Ocean using satellite-tagged animals to gather data about their world.
- A project entitled Distribution and Abundance of Marine Birds, Mammals and Zooplankton Relative to the Physical Oceanography of the Gulf of Farallones and Cordell Bank aims to 1) understand the effects of varying oceanographic regimes on predator-prey relationships and food-web dynamics in the central California region and 2) provide a scientific basis for the design and implementation of a marine protected area.
- Structure of Populations, Levels of Abundance and Status of Humpbacks (SPLASH) is an international cooperative effort to understand the population structure of humpback whales across the North Pacific and to assess the status, trends and potential human impacts to this population.
- NOAA Fisheries Gray Whale Stock Assessment is an ongoing project that conducts annual surveys of the gray whale population on its northward and southern migrations along the U.S. West Coast. Aerial surveys assess the health of cow-calf pairs, and land-based biologists observe group dynamics, behaviors and feeding activities.
- The Center for Integrated Marine Technologies' (CIMT) Wind to Whales project uses emerging technology to assess the processes underlying the dynamics of the coastal upwelling ecosystems along the California coast.