SEI WHALE

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© Larry Foster, Earth Views

Balaenoptera borealis

Federal status: Endangered (June 2, 1970)
State status: Endangered (December 20, 1989)

Description: Large whale. Dark, steel gray in color with a lighter throat and chest and light mottling on the flanks and belly. Dorsal fin up to 60 cm (23.6 in) tall, strongly hooked, located near the midpoint of the body. Ventral grooves only extend to midpoint between flippers and navel. Baleen composed of very fine brisdes (about 0.1 mm (0.004 in) in diameter at base, compared to 0.3 mm (0.12 in) or greater for other Baleen whales); shiny black. Single ridge on top of head. Adults reach 18.5 m (60 ft) total length. Usually found in small family groups of 4 or 5 but occasionally form larger concentrations when feeding. Found in coastal and off-shore waters. Matures at 7-10 years of age; 1 calf produced every 2-3 years. Feeds near the surface on zooplankton and small fish.

Habitat: Marine deepwater.

Distribution: Found throughout the oceans and seas of the world but tends to avoid polar waters. There are only 4 records from the Gulf of Mexico; 2 from Louisiana, near Fort Bayou, Plaquemines Parish, April 1956, and from Marsh Island in 1990.

Reasons for decline: Overharvest.

March 2004

Conservation efforts: Very little reliable data on population levels exist. Need more data.