Sanctuary Integrated Monitoring Network
Monterey Bay National Marine Sanctuary
Marine Mammals_ map
Figure 1. Marine Mammal hotspots within the Monterey Bay National Marine Sanctuary. [View Larger]
Referred by some as the "Serengeti of the Sea" due to the large number of marine mammal species, Monterey Bay National Marine Sanctuary is known both nationally and internationally as a "hot spot" for viewing marine wildlife. Shorelines and offshore waters provide many opportunities for viewing whales, dolphins, seals, sea lions and sea otters.

The sanctuary has one of the most diverse and abundant assemblages of marine mammals in the world, including twenty-nine species of cetacean (whales, dolphins, and porpoises), six species of pinniped (seals and sea lions) and one species of fissiped (sea otter). This diversity and abundance is due to a number of important, related factors: Until recently, most of our understanding of marine mammals came from shore- and boat-based observations. New areas of study include documenting long-range migrations of animals traveling far from shore. These studies ­ which are enabled by satellite transmitters attached to pelagic seabirds, mammals, fishes, sharks and turtles ­ are expanding our understanding of marine wildlife and the sanctuary's role in their feeding and migratory patterns.
Reporting tagged, sick/injured, or dead marine mammals on the beach

Following these guidelines will improve response time to the marine mammal. In all cases, do not touch or closely approach the animal, and please advise others to do the same. When contacting one of the groups below, be sure to describe the condition of the animal, its specific location, and provide your contact information.

To report tags observed on live marine mammals, go to this web site:

Live stranded seal, sea lion, whale, dolphin, or turtle: call the Marine Mammal Center at 831-633-6298.

Live or dead stranded sea otter: call the Monterey Bay Aquarium at 831-648-4840.

Dead stranded seal, sea lion, whale, dolphin, or turtle in MONTEREY COUNTY (south of Pajaro River): call Moss Landing Marine Laboratories at 831-771-4422.

Dead stranded seal, sea lion, whale dolphin, or turtle in SANTA CRUZ COUNTY (north of Pajaro River): call the Long Marine Lab Stranding Network at 831-212-1272.

The most studied cetacean in the sanctuary is the eastern Pacific population of the gray whale, Eschrictius robustus. Gray whales spend winter months in shallow lagoons in Baja California, Mexico. Calves are born there, and the whales mate in the tropical waters.

In the spring, they migrate north through the sanctuary to rich feeding areas in the Bering, Beaufort and Siberian Seas. Then, as sea ice forms in winter, the whales head south again. This annual voyage along North America's West Coast can be as long as 17,700 kilometers (11,000 miles).

In the 1700s, whalers followed the gray whale migration to hunt and slaughter the giants for whale oil and other products. Lookouts were placed along points and promontories, and when whales were sighted, shore whaling vessels were launched. Some of California¹s coastal towns, including San Simeon and Pacific Grove, were whaling stations.

Today, researchers use the very same lookout spots to monitor and count the whales on their annual migration.

Now protected from whalers, gray whales are still hunted by predatory orcas (killer whales), Orcinus orca. Hunting in family groups, or pods, orcas follow gray whale cow-calf pairs on their spring northward migration and attack them as they cross Monterey Bay.

Other large whales, including blue whales, Balaenoptera musculus musculus, and humpback whales, Megaptera novaeangliae, move into the sanctuary in the summer and fall to feed in its productive waters. Movements of smaller cetaceans are likely associated with local changes in oceanographic conditions and prey abundance.

Of the six pinniped species found in the sanctuary, three are commonly seen from shore: the California sea lion, Zalophus californianus; the northern elephant seal, Mirounga angustirostris; and the Pacific harbor seal, Phoca vitulina. The northern fur seal, Callorhinus ursinus, migrates in offshore waters and is rarely seen near land. The Steller sea lion, Eumetopias jubatus, has experienced declining numbers throughout its range, while the Guadalupe fur seal, Arctocephalus townsendi, has been reported from stranding records.

Just a portion of the Northern Elephant seal (Mirounga angustirostris) colony at Piedras Blancas.

Humpback whale breaching

Pinnipeds use sanctuary waters for feeding, migration and breeding.

In the spring months, sea lions and fur seals migrate through the sanctuary to breeding areas in southern California and Baja California, including the Channel Islands National Marine Sanctuary. In August and September, they take advantage of late summer productivity along the central coast to travel to northern feeding areas.

Sea lions can be observed resting on offshore rocks throughout the Monterey Bay sanctuary. Some sea lions become accustomed to human environments and haul out on docks and piers, begging for food from eager tourists.

During winter months, northern elephant seals travel through the sanctuary on their way to and from breeding areas. Most elephant seals breed on the Channel Islands, while some travel as far south as Baja California.

The easiest places to observe elephant seals during their breeding season are Año Nuevo and Piedras Blancas: Harbor seals haul out on nearshore rocks, intertidal shelves and isolated beaches throughout the sanctuary to rest and bear their young. Residential or non-migratory, harbor seals stay fairly close to their hauling sites throughout their lives.

Elkhorn Slough supports a large population of harbor seals, and another very scenic place to observe them is Point Lobos State Reserve. Harbor seal pupping occurs from February into May. One of the best places to observe harbor seals during the pupping season is at Hopkins Marine Life Refuge, where these seals give birth and nurse pups only meters away from downtown Monterey.

Sea Otter
Southern sea otters, Enhydra lutris nereis, once occurred in a continuous range from northern California to Baja California, but excessive hunting in the 1700s nearly wiped out the species. A small group survived the fur trade and was discovered in Big Sur in 1938 during the construction of the Big Sur Highway.

This group has expanded north and south, with most of its range occurring within the sanctuary. The 2016 census of southern sea otters (3,272) is based on a 3-year average of combined counts from the mainland range and San Nicolas Island. This is the first year that the official index has exceeded 3,090, the Endangered Species Act delisting threshold suggested by the U.S. Fish and Wildlife Service (the threshold would need to be exceeded for 3 consecutive years before delisting consideration).


Tagging of Pacific Pelagics (TOPP)
Since 2000, TOPP had been exploring the Pacific Ocean using a carefully selected group of animals to gather data about their world. A pilot program of the Census of Marine Life, it is an international endeavor to determine what lives, has lived and will live in the world's ocean. Ultimately, scientists will draw upon their data to build models of Pacific ecosystems.

harbor seal
Collaborative Survey of Cetacean Abundance and the Pelagic Ecosystem (CSCAPE)
West Coast CSCAPE is a collaboration between NOAA Fisheries and the National Marine Sanctuary Program to assess the abundance and distribution of marine mammals and to characterize the pelagic ecosystem out to approximately 300 nautical miles off the U.S. West Coast.

Center for Integrated Marine Technologies (CIMT): Wind to Whales
CIMT is an interdisciplinary coastal research consortium that integrates data collected via remote sensing, moorings and ship-board surveys in the Monterey Bay region. CIMT uses these technologies to investigate linkages among coastal upwelling, nutrient delivery, phytoplankton and organisms at higher trophic levels (squid, fishes, seabirds, sea turtles, seals and whales).
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