SPECIES OF CETACEANS IN U.S. WATERS PROTECTED UNDER THE ESA Blue Whale:(Balaenoptera musculus) Bowhead Whale:(Balaena mysticetus) Fin Whale:Balaenoptera physalus) Humpback Whale:Megaptera novaeangliae) Right Whale:(Balaena glacialis) Sei Whale:(Balaenoptera borealis) Sperm Whale:(Physeter macrocephalus) FEEDING HABITS As is indicated in the discussions of individual species, various species of whales feed at different levels on the food chain. Some species feed on the swarms of zooplankton (copepods and euphausiids, or "krill"). Others feed on schooling fish. The sperm whale feeds on squid. The type of prey may determine how a specific species feeds. Some may be called lungers--they take huge gulps of water containing their prey. Others are skimmers--they swim along with their mouths open before straining out their prey. One of the more interesting feeding methods has been observed in humpback whales. They sometimes construct bubble nets around a school of fish and then lunge up through the bubble net to get their food. REPRODUCTION Most of the larger whales have a very low reproductive rate: females only have a single calf every 2-4 years. With very small populations this low rate of reproduction means that it may take decades for some species to recover to their former population levels. Even under the best conditions, it will take over a hundred years for the right whale to recover. For some species of whales, the calves are born during the part of the animal cycle when the animals are in warmer waters, and the adults are not feeding. Unlike dolphins and porpoises, a calf spends a relatively short period of time with its mother. Calves usually become independent within a single year. During that time, a calf gains weight very rapidly. Whale milk is very rich, and a blue whale calf may gain almost 200 pounds per day. POSSIBLE THREATS TO RECOVERY Although commercial whaling currently does not present a threat to the survival of the baleen whales, loss of habitat and other human activities may make recovery more difficult. Collisions with vessels, oil spills and other changes in water quality, coastal development, and increasing noise created from the use of oceanic resources may all affect the whales. Fisheries may affect whales in two ways. First, whales may become entangled in fishing gear. As an example, each year several humpback whales are entangled in fishing gear along the east coast of the United States and Canada. Second, fisheries may complete with whales for food, such as herring. Increased noise or boat traffic may cause whales to alter their behavior. There is evidence that humpback whales in Hawaii may have changed their use of near-shore waters where calves are raised by their mothers because of increasing human activity. Migrating bowhead whales may move further offshore to avoid human-caused noise. Although we do not have a full understanding of the possible impacts, pollution could also affect whales. Many contaminants are stored in a whale's blubber for long periods of time. Pollutant loads are usually lower in baleen whales than in dolphins and porpoises. Deterioration of the environment could possibly affect the whales in another way: if pollution and other factors reduce the number of fish and crustaceans, the food available to the whales could also be reduced. Biological data taken from: National Marine Fisheries Service, 1984. Marine Fisheries Review, "The Status of Endangered Whales." National Marine Fisheries Service, Scientific Publications Office, Seattle, Washington. Additional information about whales and other marine species protected by the Endangered Species Act and Marine Mammal Protection Act is available via the Internet at: http://kingfish.ssp.nmfs.gov/tmcintyr/prot_res.html or by writing to: NOAA Public Affairs/Outreach Unit 1305 East-West Highway, Station 1W204 Silver Spring, Maryland 20910

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