M. Lynne Corn (l)
Specialist in Natural Resources Policy
Environment and Natural Resources Policy Division
April 14, 1995
Of all the large whale species, the northern right whale is the most endangered. Prized for centuries for its copious oils and baleen ("whalebone"), it was intensely hunted into the 20th century. Fewer than 350 remain in the northwestern Atlantic; a European population was extirpated by the 1500s.(2) Because of this severe depletion, the right whale was the first whale species to receive international protection, beginning in 1935. It is now protected by a host of national laws and international treaties. However, its numbers remain low, even though the California grey whale population has almost tripled under the same laws.(3) Scientists surmise that right whale recovery may be impeded by habitat degradation, propeller and fishing gear injuries and fatalities, and competition for food. In an attempt to boost the population, three key areas of the right whales' range within Federal jurisdiction have been designated as critical habitat. The National Marine Fisheries Service is considering additional measures to reduce harmful human interactions with right whales.
COMMON NAMES: Northern right whale.(4) Also, North Atlantic right whale and black right whale
SCIENTIFIC NAME: Eubalaena glacialis, family Balaenidae (baleen whales)
HISTORIC RANGE: From the coast of Labrador to Delaware Bay, and south to the Gulf of Mexico, Bermuda, and Florida. Also the eastern Atlantic in and around the Bay of Biscay (bordered by France and Spain) down to the northwestern coast of Africa. At least 10,000 and perhaps 50,000 or more right whales used to live in the northern Atlantic Ocean.
CURRENT RANGE: Twentieth century sightings have occurred along Newfoundland, the St. Lawrence River, and Cape Cod Bay to the Carribean Sea. Right whales are no longer seen in certain inshore areas (where they once were common) such as Delaware Bay, Long Island, and in the Strait of Belle Isle between Newfoundland and Labrador. They are now usually found in five areas including Canada's Bay of Fundy and Browns and Baccaro Banks (south of Nova Scotia), and portions of the coasts of Florida, Georgia, and Massachusetts.
POPULATION TRENDS: The estimated current northwestern Atlantic population is less than 350. Although this species has been protected under various laws for 60 years, the population seems to have remained fairly constant during this time.
HABITAT: Right whales reside in shallow waters that border islands and coastlines. Pregnant cows migrate each year from feeding grounds in the north to the calving grounds located in the southern portion of their range. It is unknown where the rest of the population overwinters, although up to 20 percent may remain in the coastal waters off Massachusetts.
Each winter, between 7 and 17 calves are born along the coast between the mouth of the Altamaha River, Georgia, and Sebastian Inlet (south of Cape Canaveral), Florida. Cows give birth every three to five years.
Right whales eat small invertebrates called krill and copepods, which live in fairly shallow water. To catch these tiny animals, the whales swim open-mouthed to allow the water to pass over their baleen plates, which hang down from the upper jaw and are effective strainers. Fluctuations in the amount and location of available food most likely determine where the whales may be found from year to year; however, they apparently fast during the winter months.
BACKGROUND: Commercial harvest of the right whale for its oil and baleen was a profitable industry for over 800 years. The oil was used in lamps, and more recently, in cosmetics. Baleen was once processed into corset and umbrella ribs, fans, clocksprings, hairbrushes, and riding crops.
Clearly the largest threat to the right whale until recently has been human predation. It was one of the first whale species to be depleted because of its ease of harvest: the whales swim slowly and float when killed. By the 19th century, the species was severely depleted. Since the implementation of protective measures such as the International Whaling Commission ban on right whale hunting in 1949 and more recently, the Convention on International Trade in Endangered Species (CITES), the U.S. Endangered Species Act, and the U.S. Marine Mammal Protection Act (see below), only one known deliberate taking of a north Atlantic right whale has occurred.
MAJOR THREATS: The primary human factor which inhibits right whale recovery, is collisions with ships. Other threats include entrapment and/or entanglement in certain types of fishing gear, habitat degradation and reduction, and disturbance from vessels which may alter whale behavior.
The right whale is particularly susceptible to the dangers posed by ships and equipment because of its habits of resting near and on the surface as well as surface courtship and skim-feeding. Vessel encounters accounted for 7 percent of injuries and 28 percent of all known right whale deaths between 1970 and 1994. Oftentimes, the whales are not killed outright but are fatally injured by propeller blades, and eventually die because of impairment or loss of appendage function. Fishing gear that entrap and entangle whales include deep sea lobster lines, ropes, seine nets, fish weirs, and gillnets. Six percent of known right whale deaths between 1970 and 1994 were caused by entanglements, and 57 percent of right whales have scars which are believed to be from fishing gear.
Right whale habitat is being degraded or lost to shipping and military operations in key regions. Furthermore, although the 1994 critical habitat designation (see below) of three feeding and/or nursery grounds may help to curb habitat degradation, the pollution of these areas due to effluents, off-shore oil exploration and production (in the northeastern United States) and phosphorus mining (in the southeastern United States) remains a substantial concern. Pollutants may reduce the abundance of prey and may have toxic effects on the whales themselves.
Another impediment to the whales' comeback is a naturally low rate of reproduction, coupled with a relatively high mortality rate (compared to other whale species) from both human and natural factors. There is also evidence that competition for food with other whale species and some kinds of fish species may be limiting the population's growth. Sei whales, mackerel, and herring (which feed on the same species as right whales) appear to be expanding into former right whale habitat.
Some scientists are concerned that there simply may not be enough animals left for the species to recover. A "genetic bottleneck" within the species has led to inbreeding among the few hundred remaining whales, severely reducing the ability of the whales to reproduce successfully and contributing in part to a high infant mortality rate. Although no specific scientific evidence exists to support the latter concern, a significant bottleneck would hinder the effectiveness of conservation efforts.
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