Marine Mammals

Overview

The Channel Islands and surrounding waters support a great diversity of marine mammals, which can be divided into three groups: 1) whales, dolphins and porpoises (cetaceans); 2) seals and sea lions (pinnipeds); and 3) the southern sea otter.

Cetaceans live their entire lives at sea, while pinnipeds come ashore periodically to rest, breed, bear young, or molt. Pinnipeds depend on several haulouts and rookery sites throughout the Channel Islands. In California, sea otters normally spend their entire lives at sea, though some occasionally haul out on land. Marine mammals feed on fishes and invertebrates, which feed on other marine life in the Channel Islands region. The abundance and distribution of marine mammals is an important indication of the general health and ecological integrity of the sanctuary.

While all marine mammals are protected under the Marine Mammal Protection Act of 1972 (MMPA), some marine mammals are further protected under the federal and state Endangered Species Act. The Channel Islands provides an important habitat for at least 10 species of endangered marine mammals.

Whales, Dolphins And Porpoises

At least 33 species of cetaceans have been reported in the sanctuary region (Leatherwood et al. 1982; Leatherwood et al. 1987), of which seven are listed as endangered. Most of the reports involve live sightings although a few are known only from strandings. Common species found in the sanctuary include: Long-beaked common dolphin, Short-beaked common dolphin, Bottlenose dolphin, Pacific white-sided dolphin, Northern right whale dolphin, Risso’s dolphin, California gray whale, Blue whale, and Humpback whale. In winter and spring during the gray whale migrations, orcas are frequently reported in the region.

Humpack calf (Megaptera novaeangliae) in the kelp. Photo by Robert Schwemmer, NOAA ONMS.
Humpack calf (Megaptera novaeangliae) in the kelp. Photo by Robert Schwemmer, NOAA ONMS.

Humpback whale tail (Megaptera novaeangliae). Photo by Robert Schwemmer, NOAA ONMS.
Humpback whale tail (Megaptera novaeangliae). Photo by Robert Schwemmer, NOAA ONMS.

Seals and Sea Lions

The productive waters and relatively undisturbed environment of the sanctuary provides vital habitat for pinnipeds, offering important feeding areas, breeding sites, and haul-outs. Three species commonly found throughout or in parts of the sanctuary are the California sea lion, northern elephant seal, and Pacific harbor seal. Rare or uncommon species sighted within the sanctuary include the northern fur seal, the Steller sea lion and the endangered Guadalupe fur seal.

California sea lions (Zalophus californianus) off of Gull Island. Photo by Robert Schwemmer, NOAA ONMS.
California sea lions (Zalophus californianus) off of Gull Island. Photo by Robert Schwemmer, NOAA ONMS.
A whimbrel shorebird walks past a Northern elephant seal (Mirounga angustirostris). Photo by Robert Schwemmer, NOAA ONMS.
A whimbrel shorebird walks past a Northern elephant seal (Mirounga angustirostris). Photo by Robert Schwemmer, NOAA ONMS.

Sea Otters

Sea otters were common in the Channel Islands until prolonged periods of hunting led to local extinction at the Islands and severe depletion along the mainland California coast. After an international treaty in 1911 banned sea otter hunting, the population has increased slowly, however with drastic fluctuations due to fishing gear entanglements, disease, shark attacks, shooting, and starvation. In 2007 the USGS Western Ecological Research Center sea otter spring survey found 106 independent sea otters and zero confirmed pups south of Point Conception.

Although long-term status of the sea otter population is unclear, the geographic range of the population has expanded to the north and south. The recovering California population of sea otters now ranges from Point Conception north to Año Nuevo Island in Santa Cruz County. As a result of threats to sea otters due to their small population and limited range, a translocation project to reintroduce otters to part of their historic range was started in 1988, yet met with limited success. Between 1988 and 1990, 140 otters were translocated to San Nicholas Island and while some stayed, many swam away, died, or disappeared and were unaccounted for. As of 2010 only 46 otters were found at the San Nicholas. Sea otters are now occasionally spotted in the sanctuary, however the possibility remains that they could reestablish their range within sanctuary boundaries (USFWS 2005). The southern sea otter is listed as threatened under the federal Endangered Species Act and fully protected under California state law.

Humpbacks lunging
Fig 1. Humpback whales lunge feeding in the Sanctuary
Photo: L. Gordon

Photo Library

No photos are currently available for this section.

Map Repository

No maps are currently available for this section.

Project Database

Historic

Biogeographic Assessment of the Channel Islands National Marine Sanctuary

The Channel Islands National Marine Sanctuary (CINMS) off the coast of Southern California was designated in 1980. In 2005, NOAA’s Office of National Marine Sanctuaries and CINMS were considering six alternatives for adjusting the sanctuary’s boundaries. Identifying how the six options overlaid with the distribution of marine resources was a critical consideration. To address this need, we conducted a biogeographic assessment.

Ongoing

Channel Islands Naturalist Corps

Channel Islands Naturalist Corps volunteers are trained by CINMS and CINP to educate the public on board local marine excursion vessels conducting whale watch tours, natural history tours, and island trips. Channel Islands Naturalist Corps volunteers are trained to conduct citizen science on marine mammal field identification and general research. Research objectives of the program include the development of a comprehensive database of incidental marine mammal sightings and reports collected in the Santa Barbara Channel, CINMS and CINP.

Ongoing

Long Term Monitoring Using Ocean Noise Reference Stations

The objective of this project is to establish a NOAA-operated network of ten ocean noise reference stations (ONRS) in US waters to monitor long-term changes and trends in the underwater ambient sound field.

NOAA’s ONRS Network will detect and characterize:

(1) sounds produced and used by living marine resources (e.g., endangered marine mammals)
(2) natural sources of noise from physical oceanographic processes
(3) anthropogenic noise sources that contribute to the overall ocean noise environment.

Ongoing

Monitoring Shipping Noise in the Santa Barbara Channel

Simultaneous AIS (Automatic Information System) ship tracking data and underwater hydrophone data have been collected in the Santa Barbara Channel since 2007. These data allow measurement of the source level of individual vessels transiting through the Santa Barbara Channel.

Ongoing

Monitoring whales by Cascadia Research Collective

Cascadia Research is a non-profit (501c3) scientific and education organization based in Olympia, Washington, USA. We primarily conduct research needed to manage and protect threatened marine mammals.

Ongoing

Photo-identification of Blue Whales

The focus of this project is to collect identification photographs of blue whales to examine movements, migratory destinations, stock structure, and behavior, and to estimate abundance and trends in abundance.

Historic

Sanctuary Aerial Monitoring and Spatial Analysis Program

Sanctuary Aerial Monitoring and Spatial Analysis Program (SAMSAP) was a long-term aerial monitoring program that collected data on vessel and visitor use patterns as well as cetacean populations within CINMS. It provided vital data for management, research, and emergency response needs.

Ongoing

Tagging of Pacific Predators (TOPP)

The Tagging of Pacific Pelagics (TOPP) research program aims to understand the migration patterns of large predators in the North Pacific basin and how these animals act and interact in their open ocean habitats. By using satellite tagging techniques, TOPP researchers follow the movements of different species across multiple trophic levels (i.e., the food web) and in relation to physical oceanographic features in order to piece together a whole ecosystem picture.

Ongoing

Underwater Behavior of Large Whales Using Suction-cup Attached Tags

This project examined underwater movements, behavior, and vocalizations of individual blue, fin, and humpback whales using suction-cup tags. Tags included a variety of instrument packages.