Different Types Of Closes

A controversial animal welfare issue, harp seal pups are commercially harvested for their white fur.

Collectively, seals, sea lions and walruses make up the pinnipeds, a group accounting for nearly one quarter of all marine mammal species. As members of the order Carnivora, pinnipeds are biologically related to terrestrial carnivores like bears and wolves. The 33 living pinnipeds are divided among three families: the Phocidae, or true or earless seals; the Otariidae, the sea lions and fur seals; and the Odobenidae, the walrus. All pinnipeds are protected under the Marine Mammal Protection Act, which works to conserves viable populations of the species.

Northern 'True' Seals

Under exemption, Alaska Natives are permitted to harvest harbor seals for subsistence purposes.

The Phocidae, or "true" seals, lack external ears, have rear flippers that point backwards and move on land by undulating or "galloping." Phocids have been further divided into two sub-families: the Phocinae and the Monachinae. The Phocinae, loosely classified as the northern "true" seals, include 10 species: the hooded seal, bearded seal, grey seal and the species of the Phoca genus, namely the caspian seal, ribbon seal, harp seal, ringed seal, spotted seal, Saimaa seal, baikal seal and harbor seal. Loss of sea ice due to global climate change has prompted concern about "ice seals," notably the bearded, ringed, spotted and ribbon seals. The bearded and ringed seals have been proposed for listing; the spotted seal is listed as threatened; and the ribbon seal is a "Species of Concern." A subspecies of the ringed seal, the Saimaa seal has been federally listed as an endangered species, with less than 250 seals left in the world. Unlike other ringed seals, the Saimaa seal lives only in freshwater, isolated to Lake Saimaa in Finland.

Southern 'True' Seals

One of the world's most endangered seals, Hawaiian monk seal populations are currently declining at 4 percent annually.

The Monachinae subfamily, or southern "true seals," consists of the Hawaiian and Mediterranean monk seals, Weddell seal, crabeater seal, leopard seal, Ross seal and the northern and southern elephant seals. The Weddell, crabeater, leopard and Ross seals are all endemic to Antarctica. Named for the males' enlarged proboscis, the elephant seals are the largest phocid, with the southern species besting the northern in size. Both the Hawaiian and Mediterranean monk seals are among the world's most endangered species, with only 1,200 and 800 seals remaining, respectively. With current downward trends in both populations, biologists fear the two species face imminent extinction, due in large part to direct and indirect human impacts. Tragically, their close relative, the Caribbean monk seal, was last sighted in 1952 and on June 6, 2008, the National Marine Fisheries Service declared the species extinct.

Seal Lions

Identified as a "vulnerable" species, Galapagos sea lion populations have been negatively effected by 25 years of El Nino cycles.

The Otariids, or eared seals, have external ear flaps or pinnae and can rotate their hind flippers forward to walk on land. Otariids are traditionally divided into two sub-families: the Otariiane and the Arctocephalinae. The Otariiane, or sea lions, consist of five species living in both hemispheres: the Steller or northern seal lion, Australian sea lion, South American sea lion, New Zealand sea lion, and Zalophus californianus consisting of the California, Galapagos and the now extinct Japanese subspecies. Of these, both the Calfornia and the Steller sea lions inhabit United States waters along the Pacific Coast. The largest member of the Otariids, the Steller sea lion, has experienced significant population declines. For management purposes, National Marine Fisheries Service has divided the population into the Western and Eastern "distinct population segments." The Western Steller seal lion population -- residing in the central and western Gulf of Alaska, Aleutian Islands and Asia -- declined an average of 5.4 percent per year since 1976. In 1990, the Western Distinct Population was listed as an endangered species. The Eastern Distinct Population, a federally threatened species, includes Steller seal lions residing in southeast Alaska, British Columbia, California and Oregon.

Fur Seals

Once hunted to economic extinction, New Zealand fur seal populations are now gradually increasing through most of their range.

The fur seals of the Arctocephalinae subfamily are named for their dense, thick fur, a trait that made them particularly susceptible to commercial harvest. The fur seals consist of nine species: the northern fur seal and the southern fur seals which includes the South American, New Zealand, Galapagos, Antarctic, Juan Fernandez, South African and Australian, Guadalupe and Subantarctic species. All are found in the southern hemisphere, with the exception of the northern and Guadelupe fur seals, which can be found in United States waters along the Pacific Coast. The Guadelupe fur seal were commercially hunted to near extinction in the 1700s and 1800s. In 1985, the species was listed as threatened throughout its limited range. The northern fur seal also experienced declines due to unregulated harvest. A second decline occurred due to an ill-conceived experimental female harvest which ended 1968. The Pribilof Island population continues to decline, leading to a characterization of "depleted" under the Marine Mammal Protection Act.

Walrus

Walrus' scientific name -- Odobenus -- translates to "the one that walks on the teeth".

The biggest seal species to inhabit the Arctic Ocean, walruses are best known for their overgrown canine teeth or tusks. Today, they are the sole member of the Odobenidae family, but during the Miocene and Pliocene eras, more than 14 species of walrus lived on the planet. Walruses are found in the Arctic ice packs of both the Atlantic and Pacific oceans. Like the "true" seals, walruses lack external ears. However, they are similar to the Otariids in the ability to rotate their hind feet forward.

Compared to other seals, they have thick skin that is covered in short, bristly hair. Walruses are the only pinniped not managed under the National Marine Fisheries Program, but rather under the jurisdiction of the United States Fish & Wildlife Service.

Century bird cages

Thursday, May 16, 2013