斑海豹种

分布

斑海豹分布的西北太平洋的高纬度寒冷水域，主要分布在楚科奇海、白令海、鄂霍次克海、日本海和中国的渤海、黄海北部。

外形特征

斑海豹身体呈纺锤形，头圆生有触须，没有外耳廓。四肢特化成鳍脚，趾间有蹼。雌性斑海豹体型大于雄性。出生的小海豹全身被白色的胎毛包裹。

习性

斑海豹每年都要换毛。它们有洄游的行为，食物主要为鱼类和头足类。3年以后达到性成熟，为一雄多雌生殖型，在每年的1~3月份繁殖，产仔在浮冰上，每胎产一仔。

分类

在谢夫（Scheffer）在1958年的分类系统中，将海豹属的动物合并为一个种，种下分为5个亚种，对这个分类方法一直有很大的争议。其中西北太平洋亚种Phoca vitulina largha在形态特征方面与大西洋亚种有显著差异，与太平洋东岸种也很不同，并且与其他亚种存在生殖隔离，所以认为这个亚种应该独立为一个种Phoca largha。

保护状况

斑海豹是中国国家一级保护动物。

由于斑海豹在沿海岸线的环境活动，有时需要到礁石或海岸上休息、换毛，沿海环境的变化对其生存有一定影响。比如渤海油田的开发让沿岸自然环境发生变化，噪音和污染物增多，船只活动频繁，这都对斑海豹产生了不利影响。

The spotted seal (Phoca largha), also known as the larga seal or largha seal, is a species of earless seal (or true seal, Phocidae). It inhabits ice floes and waters of the north Pacific Ocean and adjacent seas. It is primarily found along the continental shelf of the Beaufort, Chukchi, Bering and Okhotsk Seas and south to the northern Yellow Sea and it migrates south as far as northern Huanghai and the western Sea of Japan. It is also found in Alaska from the southeastern Bristol Bay to Demarcation Point during the ice-free seasons of summer and autumn when spotted seals mate and have pups. Smaller numbers are found in the Beaufort Sea. It is sometimes mistaken for the harbor seal to which it is closely related and spotted seals and harbor seals often mingle together in areas where their habitats overlap.

The reduction in arctic ice floes due to global warming led to concerns that the spotted seal was threatened with extinction. Studies were conducted on its population numbers, with the conclusion, as of 15 October 2009, that the spotted seal population in Alaskan waters is not currently to be listed as endangered by NOAA. However, as of 2026, the NOAA considers the distinct population group of southern spotted seals to be threatened.

Etymology

The scientific name originated in the Greek word for seal, phoce, and larga, the term used by the Siberian Tungus people for this seal. The English common name comes from this seal's characteristic dark, irregularly shaped spots. In Alaska, indigenous names include issuriq in Central Alaskan Yup'ik, gazigyaq in St. Lawrence Island Yupik, and qasigiaq in Inupiaq.

Description

The spotted seal is of the family, Phocidae, or "true seals". Compared to other true seals, they are intermediate in size, with mature adults of both sexes generally weighing between 82–109 kg (180–240 lb) and measuring 150–210 cm (59–83 in), roughly the same size as a harbor seal or ribbon seal. The head of a spotted seal is round, with a narrow snout resembling that of a dog.

The spotted seal has a relatively small body and short flippers extending behind the body that provide thrust, while the small flippers in front act as rudders. The dense fur varies in color from silver to gray and white and is characterized by dark, irregular spots against the lighter background and covering the entire body.

Distribution and habitat

Spotted seals are inhabitants of arctic or sub-arctic waters, often in the outer areas of ice floes during the breeding season. They tend not to live within dense drift ice. In the summer months they live in the open ocean or on nearby shores.

Spotted seals are separated into three populations. The Bering Sea population includes approximately 100,000 in the western Bering Sea near Kamchatka, in the Gulf of Anadyr in Russia, and in the eastern Bering Sea in Alaskan waters (the only population in the US). A second population of about 100,000 seals breeds in the Sea of Japan and the Sea of Okhotsk. A third population of about 3,300 seals is to the south in Liaodong Bay, China and Peter the Great Bay, Russia.

Behavior and reproduction

Spotted seals are relatively shy and are difficult for humans to approach. They can be solitary in general but are gregarious and form large groups during pupping and molting seasons when they haul out on ice floes or, if lacking ice, on land. The numerically largest groups in Alaska are at Kasegaluk Lagoon in the Chukchi Sea, near Cape Espenburg in Kotzebue Sound, and in Kuskokwim Bay on sandbars and shoals, where several thousand may collect.

Sexual maturity is attained around the age of four. January to mid-April is the breeding season. Pup births peak in mid-March.

Conservation status

On 28 March 2008, the U.S. National Oceanic and Atmospheric Administration (NOAA) initiated a status review under the Endangered Species Act (ESA) to determine if listing this ice seal species under the ESA was warranted. After an 18-month review of the status of the spotted seal, NOAA announced on 15 October 2009 that two of the three spotted seal populations, together numbering 200,000 seals in or adjacent to Alaska, are not in danger of becoming extinct, nor are they likely to become so in the "foreseeable future", even though global warming has caused a loss in arctic ice mass.