Northern Right Whale

views updated

Northern Right Whale

Balaena glacialis

Status	Endangered
Listed	June 2, 1970
Family	Balaenidae (Baleen Whale)
Description	Stout-bodied baleen whale, glossy black, often with irregular white patches.
Habitat	Pelagic.
Food	Plankton and krill.
Reproduction	Single calf at three to five year intervals.
Threats	Human predation.
Range	Oceanic

Description

The northern right whale's, Balaena glacialis, average length is about 50 ft (15 m), and its girth is often equal to its length. The head makes up nearly one-fourth of the body length. Flippers are large and spatula-shaped, and the dorsal fin is lacking. Glossy black above, it is pale beneath, often mottled with irregular white patches. The upper jaw is long, narrow, and highly arched. The lower jaw is bowed. When mature, these whales can weigh up to 50 tons (55 metric tons). A distinguishing characteristic of right whales is the growth of scaly patches on the head, called callosities, which form a unique pattern used to identify individual whales. Callosities are caused by a small parasitic crustacean, known commonly as whale lice.

This species is also known as the black right whale, North Atlantic right whale, and Biscayan right whale. It is also classified as Eubalaena glacialis.

Behavior

The northern right whale is a slow-swimming browser that travels alone or in small groups, feeding on plankton and other invertebrates. It migrates slowly north and south along the coastline with the seasons. Swimming with its mouth open, it strains plankton from the water through its baleen.

After a gestation period of 12 months, a northern right whale cow gives birth to a single calf between December and March. Cows give birth at three-to-five-year intervals. Juveniles reach maturity between five and seven years of age.

Two widely separated blow holes cause the right whale's spout to be V-shaped, allowing positive identification of the species from a distance.

Habitat

This is an inshore species that prefers shallow waters bordering islands or along the coastlines of uninhabited areas. Because it feeds exclusively on zooplankton, the size of the right whale population could be used as an indicator of the health of the lowest levels of the marine food chain.

In the North Atlantic, the whale is found along the eastern seaboard throughout the year. Its winter calving area is in the coastal waters of the southeastern United States, especially the shallow waters off the coast of Florida and Georgia. Only adult females and very young juveniles are usually seen in this area. During late winter and early spring, this species begins moving north. By late summer it is seen in the Bay of Fundy or on the southeastern Scotian shelf. The species leaves the northern feeding grounds beginning as early as October and moves to its wintering areas without any extended pause.

Similar to the near coastal continental shelf distribution of the species in the North Atlantic, the northern right whale in the North Pacific occurs over continental shelf areas. Sightings have been reported from as far south as Baja California, and as far north as the sub-Arctic waters of the Bering Sea and Sea of Okhotsk in the summer.

Distribution

The right whale was historically found in oceans throughout the northern hemisphere, mostly within the confines of the continental shelf of North America. Off the Pacific coast, it was seen occasionally from the Aleutian Islands south to Baja, California. It was once more common off the Atlantic coast from the Bay of Fundy south to the Florida coast. Because of extensive whaling, the northern right whale was considered virtually extinct by the middle of the 20th century. A northern right whale population in the northeastern Atlantic off the European coast was eliminated by whaling as early as 1530.

The northern right whale is recognized as the world's most endangered large whale species. Recent mortalities off the Atlantic coast of the United States have caused escalating concern for the western North Atlantic population, especially with regard to the population's vulnerability to human interaction. Since 1995, there have been 14, possibly 15, known serious injuries and/or mortalities of right whales off the Atlantic coast (five due to entanglement, three due to ship strikes, five due to unknown or natural causes, and one death in 1996 due to ship strike of a whale injured by an entanglement in 1995). Furthermore, in early 1996, an increase in estimated mortalities was reported for the years 1994 and 1995. The North Pacific population was never very abundant, and only about 15 right whales have been observed there in the last 50 years. The population probably numbers less than 100 animals.

The North Atlantic population migrates from feeding grounds near Newfoundland and the St. Lawrence south to the coast of Georgia and Florida and the Caribbean. About 30 cows use the coastline between Savannah, Georgia, and Key Largo, Florida, for calving each year. The remainder of a population of between 240 and 500 whales winters at an unknown site. Using photo identification techniques, scientists have estimated that the calf production in the North Atlantic population has ranged between 8 and 13 calves per year since 1981, although the recent mortalities may reduce the calving numbers.

Threats

The northern right whale was one of the first of the great whales to be hunted to the brink of extinction. It was easy to take, and when killed, it floated on the surface, allowing whalers to harvest oil and bone with minimum effort. For whalers, it was certainly the "right whale" to catch.

Significant uncertainties remain concerning the current population status and trends. Regardless of the uncertainties, the precarious state of the right whale population strongly suggests that human activity, which results in disturbance, and thus, an increased potential for injury and mortality, may have a greater impact on population growth rates and trends relative to other whale species.

Conservation and Recovery

Northern right whales were initially protected by a League of Nations resolution that took effect in 1935. Protection was continued by the International Whaling Commission (IWC) beginning in 1946. The species is considered Endangered by the Convention on International Trade in Endangered Species (CITES) and is protected under several laws passed and enforced by Canada. In the United States, whale protection was authorized by the Marine Mammal Protection Act of 1972 and strengthened by the Endangered Species Act in 1973. With few exceptions, these protective laws and international agreements have been observed in the North Atlantic. In spite of this fact, the right whale population has recovered only slightly, if at all.

In 1986, five organizations studying northern right whales banded together to form the North Atlantic Right Whale Consortium. Supported by congressional funding, this consortium sponsors research by marine biologists from the Woods Hole Oceanographic Institute, the New England Aquarium, the Center for Coastal Studies, the University of Rhode Island, and Marineland of Florida.

In 1988, the National Marine Fisheries Service (NMFS) initiated recovery efforts for the northern right whale and the humpback whale. Under the Endangered Species Act, the NMFS, part of the Commerce Department, is responsible for developing and implementing recovery plans for federally listed marine species.

The Final Recovery Plan for the northern right whale was released in 1991; it included specific guidelines for avoiding contact with the whales. Human contact, be it by pleasure boats, whale watch vessels, aircraft and other vehicular traffic, is a serious threat to the population. In 1997, a modification was announced to further protect the whales by more strictly limiting contact. The interim final rule restricts approaches within 500 yards (460 m) of a northern right whale, whether by vessel, aircraft or other means, in an attempt to reduce the current level of disturbance and the potential for vessel interaction and injury. This rule requires right whale avoidance measures if a vessel or aircraft is within the 500 yard (460 m) restricted area.

Generally, vessels are required to immediately depart from the area at a slow, safe speed in a direction away from the whale. Exceptions are provided for emergency situations, where certain authorizations are provided for aircraft operations (unless the aircraft is conducting whale watch activities), for certain right whale disentanglement/rescue efforts and investigations, and for a vessel restricted in its ability to maneuver and unable to comply with the right whale avoidance measures.