Hydrodamalis gigas

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	MAMMALIA	SIRENIA	DUGONGIDAE

Scientific Name:

Hydrodamalis gigas

Species Authority

Infra-specific Authority:

(Zimmermann, 1780)

Common Name/s:

English

–

Steller's Sea Cow

Assessment Information [top]

Red List Category & Criteria:

Extinct ver 3.1

Year Assessed:

2008

Assessor/s

Domning, D., Anderson, P.K. & Turvey, S.

Evaluator/s:

Reynolds III, J.E. & Powell, J.A. (Sirenia Red List Authority)

Justification:
The last population of Steller's Sea Cow was discovered by a Russian expedition wrecked on Bering Island in 1741. The genus is thought to have become extinct by 1768.

History:

1996	–	Extinct (Baillie and Groombridge 1996)
1994	–	Extinct (Groombridge 1994)
1990	–	Extinct (IUCN 1990)
1988	–	Extinct (IUCN Conservation Monitoring Centre 1988)
1986	–	Extinct (IUCN Conservation Monitoring Centre 1986)

Geographic Range [top]

Range Description:	Steller's Sea Cow was known from the Bering Sea. The last population was discovered by a Russian expedition wrecked on Bering Island in 1741. It is likely that a population also persisted in at least the western Aleutian Islands into the 18th century (Domning et al. 2007). A catalogue of osteological specimens of H. gigas in the world’s museums, with a history of their collection, was published by Mattioli and Domning (2006). In the Pliocene and Pleistocene, Hydrodamalis occurred from Japan to Baja California, Mexico (Domning 1978; Domning and Furusawa 1995), a range that coincided with that of the Sea Otter Enhydra lutris.
Countries:	Regionally extinct: Russian Federation; United States

Range Description:

Steller's Sea Cow was known from the Bering Sea. The last population was discovered by a Russian expedition wrecked on Bering Island in 1741. It is likely that a population also persisted in at least the western Aleutian Islands into the 18th century (Domning et al. 2007).

A catalogue of osteological specimens of H. gigas in the world’s museums, with a history of their collection, was published by Mattioli and Domning (2006).

In the Pliocene and Pleistocene, Hydrodamalis occurred from Japan to Baja California, Mexico (Domning 1978; Domning and Furusawa 1995), a range that coincided with that of the Sea Otter Enhydra lutris.

Countries:

Regionally extinct:

Russian Federation; United States

Population [top]

Population:	Steller's Sea Cow was discovered in 1741 in the shallow waters around the uninhabited Commander Islands. The relict Bering Island population was studied by Georg Steller (a naturalist and physician onboard Vitus Bering's ship wrecked on the island in 1741). The sea cow was an easily available source of meat and the islands became a regular stop-over and stocking up point for Russian fur hunters until 1762–1763. Ruthlessly hunted, Steller's Sea Cow was probably extinct by 1768. Turvey and Risley (2006) presented a preliminary mathematical model of its extinction dynamics, providing evidence that the initial Bering Island sea cow population must have been higher than higher than the 1,500 animals suggested by Stejneger (1887) to allow the species to survive even until 1768.

Population:

Steller's Sea Cow was discovered in 1741 in the shallow waters around the uninhabited Commander Islands. The relict Bering Island population was studied by Georg Steller (a naturalist and physician onboard Vitus Bering's ship wrecked on the island in 1741). The sea cow was an easily available source of meat and the islands became a regular stop-over and stocking up point for Russian fur hunters until 1762–1763. Ruthlessly hunted, Steller's Sea Cow was probably extinct by 1768. Turvey and Risley (2006) presented a preliminary mathematical model of its extinction dynamics, providing evidence that the initial Bering Island sea cow population must have been higher than higher than the 1,500 animals suggested by Stejneger (1887) to allow the species to survive even until 1768.

Habitat and Ecology [top]

Habitat and Ecology:	When discovered, Steller's Sea Cow inhabited the shallow cold waters around the Commander Islands in the Bering Sea, grazing on kelps.
Systems:	Marine

Threats [top]

Major Threat(s):	Hydrodamalis was slaughtered for its meat and leather. Anderson (1995) discussed the ecological interaction between sea cows, sea otters, Strongylocentrotus sea urchins, and kelp, and suggested that human predation on sea otters (resulting in a nearshore community dominated by sea urchins, which largely eliminate shallow-water kelps leading to their replacement by chemically defended deep-water species) was a major factor, along with hunting, in sea cow extinction. Turvey et al. (2006) assessed whether hunting alone would have been sufficient to wipe out the sea cow, and showed that the speed of sea cow disappearance on Bering Island indicates that hunting alone was more than sufficient to exterminate the species without having to invoke any additional ecological pressures.

Major Threat(s):

Hydrodamalis was slaughtered for its meat and leather. Anderson (1995) discussed the ecological interaction between sea cows, sea otters, Strongylocentrotus sea urchins, and kelp, and suggested that human predation on sea otters (resulting in a nearshore community dominated by sea urchins, which largely eliminate shallow-water kelps leading to their replacement by chemically defended deep-water species) was a major factor, along with hunting, in sea cow extinction. Turvey et al. (2006) assessed whether hunting alone would have been sufficient to wipe out the sea cow, and showed that the speed of sea cow disappearance on Bering Island indicates that hunting alone was more than sufficient to exterminate the species without having to invoke any additional ecological pressures.

Conservation Actions [top]

Conservation Actions:	This species is now extinct.

Conservation Actions:

This species is now extinct.

Citation:	IUCN 2008. 2008 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 11 October 2008.
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