North Atlantic Right Whale
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The North Atlantic right whale is currently one of the rarest large whales in the world, having been drastically reduced to critically low numbers by years of exploitation. Its robust, somewhat rotund, body is mostly black, with a large head that measures up to one third of the total body length. Some individuals may also bear white patches on the underside, while others have a more mottled appearance. More often, the only conspicuous feature of this great whale are the irregular patches of thickened tissue, called callosites, on the head. These callosites are inhabited by many small amphipods, known as cyamids or whale lice, and form a pattern unique to each individual whale, thus providing a means of identification. The North Atlantic right whale lacks a dorsal fin, but has large, paddle-like pectoral fins used for steering, and an enormous tail that provides propulsion with powerful vertical strokes (2) (5). The downward-curved mouth of the North Atlantic right whale contains between 200 and 270 baleen plates on each side of the upper jaw. These plates, each measuring around two metres long and fringed with fine hairs, replace teeth in Balaenidae whales, and are central to their method of feeding. The North Atlantic right whale has two blowholes situated on top of its head through which it breathes, producing a distinctive, bushy, v-shaped cloud of spray when it exhales at the surface.
North Atlantic Right Whales (Eubalaena glacialis) inhabit the Atlantic Ocean, especially between 20o and 60o N latitude. Most individuals in the western North Atlantic population range from wintering and calving areas in coastal waters off the southeastern United States to summer feeding and nursery grounds in New England waters and north to the Bay of Fundy and Scotian Shelf. In 1991, five "high use" areas were identified by the National Marine Fisheries Service: (1) coastal Florida and Georgia, (2) Great South Channel, (3) Massachusetts Bay and Cape Cod Bay, (4) Bay of Fundy, and (5) Scotian Shelf (NOAA Fisheries Office of Protected Resources Website, accessed 10 December 2009, http://www.nmfs.noaa.gov/pr/species/mammals/cetaceans/rightwhale_northatlantic.htm).
The eastern North Atlantic population may originally have migrated along the coast from northern Europe to the northwest coast of Africa. Historical records suggest these animals were heavily exploited by whalers from the Bay of Biscay (off southern Europe) and Cintra Bay (off the northwestern coast of Africa), as well as off coastal Iceland and the British Isles. During the early to mid 1900s, right whales were intensely harvested in the Shetlands, Hebrides, and Ireland. Recent surveys suggest right whales no longer frequent Cintra Bay or northern European waters.
Depending on the time of year and which hemisphere they're found, right whales will spend much of their time near bays and peninsulas and in shallow, coastal waters. This can provide shelter, food abundance, and security for females rearing young or avoiding the mating efforts of males. Four critical habitats for northern right whales are the Browns-Baccaro Bank, Bay of Fundy, Great South Channel, and the Cape Cod Bay. Each of these is distinguished by high densities of copepod populations. The first three have deep basins (150 m) flanked by relatively shallow water. Copepods are concentrated here because of convergences and upwellings driven by tidal currents. This also occurs in the Cape Cod Bay even though a deep basin isn't present.
Northern right whales tend to move through the ocean at a fairly slow pace for an animal of their size, they feed near the surface, and they float when killed; thus they were considered the "right" catch for whalers. Hunting of right whales began as early as the 10th century. These whales were hunted extensively during the 19th century, with as many as 100,000 whales slaughtered during this time. Right whales were driven close to extinction early in the 20th century and were one of the first whales to be given international protection in 1935. At the first international Convention for the Regulation of Whaling in 1935, a total ban on hunting right whales was established. The protection of this species was broadened in 1972 with the passing of the Marine Mammal Protection Act. A major issue revolving around the conservation of the right whale is habitat modification. Especially since they use shallow coastal lagoons and bays for breeding. Their numbers are stable and may even be increasing slightly in the Northwest Atlantic and off South Africa. The most current population estimate of 295 whales may represent the approximate carrying capacity. The carrying capacity could be increased though if collisions with ships and entanglement in fishing gear was decreased. It may be decades before the health of the right whale population is recovered. A recovery plan has been established with the difficult duty of managing a species that is hard to track. Luckily, activity modifications are taking place by people like the U.S. Coast Guard, U.S. Navy, ship traffic controllers in major shipping lanes, and others. Funding is always a major obstacle but support is being seen by individual institutions, states, and relevant sectors of the federal government (Cummings 1985, Katona 1999).
Northern Atlantic right whales are the most critically endangered great whale, with fewer than 300 individuals estimated. Populations of this species don't show significant signs of increasing in number, despite a ban on hunting. At the current population numbers species extinction is expected in 190 years.
Current threats to right whales include collisions with boats, since they tend to rest and feed at the surface frequently, pollution, becoming entangled in fish nets, and sonic pollution and disruption caused by military practices.
The history of research and conservation of northern right whales provides a number of lessons that may be applicable to other endangered species. First, sufficient funding must be provided to carry out an effective management program. Second, persistence and patience is needed to develop and implement a slow moving research program. Third, studies may not meet traditional scientific standards of proof because sample sizes are so small. Fourth, effective conservation will require cooperation from federal and state agencies as well as nongovernmental groups. Fifth, incidental take of a species is much harder to regulate than directed take like hunting. Lastly, we should never become complacent about the state of our knowledge (Katona 1999).
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- Michele Lee Riddle
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