Across much of their range they are sympatric with Eurasian otters (Lutra lutra), smooth-coated otters (Lutrogale perspicillata) and hairy-nosed otters (Lutra sumatrana), and there is clear evidence of niche separation between the species. Their measurements vary depending on the sex. Next, we incorporated our partial differential equation in a hierarchical statistical model. The sea otter was nearly hunted to extinction in the early 20th century. Adult males weight between 22 and 45 kilograms and measure from 1.2 to 1.5 meters.On the other hand the adult females usually weigh between 14 and 33 kilograms, and their length varies from 1 to 1.4 meters.. This population once contained over half of the world’s sea otters. Distribution: The sea otters have a flexible skeleton and their face is small and round. River otters use their tails as rudder while swimming. The sea otter’s strong, rudder-like tail and large, webbed hind feet help propel it through the water. Distribution of the Sea Otter (Enhydra lutris) Data based on Otters of the World (IOSF 2015) About IOSF. North American river otters live near permanent watersheds throughout North America, from Alaska and northern Canada south to the Gulf of Mexico. Three populations exist in Alaska, but only one (the Southwestern DPS) is listed. When sea otter populations are healthy, urchin populations are kept in check, and kelp is abundant. Typical habitats include lakes, rivers, marshes, and coastal shorelines. The International Otter Survival Fund (IOSF) is one of the world's leading otter charities. Estimated sea otter distribution in Glacier Bay from 1993-2016. Hunting during the 18th and 19th centuries greatly reduced the distribution of sea otters. The sea otter population in Washington was listed as “endangered” under Washington State’s Endangered Species Act in 1981, due to its small population size, restricted distribution, and vulnerability. Sea otters are a keystone species and play a critical role in the food web of the kelp forest, so much so that even terrestrial species are influenced by sea otter activity. Sea ice limits their northern range to below 57 degrees N lattitude, and the distribution of kelp forests limits the southern range to about 22 degrees N lattitude. There are 13 extant species of otter around the world, one of which is native to the UK. Hierarchical models are used to draw conclusions from data that arise from complex processes. Currently, oil spills are the greatest threat to the otter, as the oil can destroy the natural insulating properties of the otter’s remarkable fur. Their preferred food is crustaceans and molluscs. Hailshadow / Getty Images Habitat and Distribution . Origin & Distribution: The otter is a secretive semi-aquatic species which was once widespread in Britain. Fine-scale information on sea otter distribution, abundance, and patterns of consumption could be used to predict areas most likely to be affected by sea otter predation and allow for the incorporation of predation into models used to estimate fishery surplus production (Larson et al., 2013). Three subspecies of E. lutris are recognized today. Since the mid-1980s it has declined approximately 55-65 percent. By the 1970s, otters were restricted mainly to Scotland, especially the islands and the north-west coast, western Wales, parts of East Anglia and the West Country (though they remained common and widespread also in Ireland). Otters are carnivorous mustelids in the Lutrinae subfamily. Distribution. Main Characteristics Of The Sea Otters Anatomy. Data that arise from complex processes as rudder while swimming widespread in Britain s sea.! To the Gulf of Mexico equation in a hierarchical statistical model as rudder while swimming Canada to. 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