[24] In August, 2011, the Environment Agency announced that otters had returned to every county in England since vanishing from every county except the West Country and parts of Northern England. Estes’s observations revealed an “extraordinarily high” sea otter population around Amchitka, inhabiting a lush undersea world of kelp forests. Sea otters act to maintain a wide variety of other populations in the community. Send keyboard focus to media. Enature. The southern sea otter (above) is a federally listed threatened species. Sea otters also maintain a high level of internal heat production to compensate for their lack of blubber. Modern efforts in sea otter conservation began in the early 20th century, when the sea otter was nearly extinct due to large-scale commercial hunting. This is a graph showing population of sea otter off the cost of California. J. L. Bodkin, R. J. Jameson, J. The primary factors limiting population growth and range expansion of southern sea otters in recent years have been density-dependent resource limitation (where the number of sea otters is in equilibrium with available prey) in much of the central portion of the mainland range and white shark attacks in the northern and southern portions of the mainland range. 30 seconds . Another predator that may be responsible for the spiraling numbers of the Sea Otter is the great white shark, which causes an estimated 10% of Sea Otter deaths. Contamination of their fur by oily substances can destroy its insulating properties and lead to hypothermia and death. Behavior. A. Estes (http://biology.usgs.gov/s+t/noframe/s043.htm). Below are demographic metrics for the Kuluk Bay sea otter population. source: Information and Media Sources: Wikipedia Page. Figure Without otters, the implication is that we would cease to have kelp forests at all. 2 show growth patterns observed in three sea otter population stocks in Remnant population. Study: 77 Percent of Marine Mammals, Sea Turtles Recovering Under Endangered Species Act . Figure 2493 Portola Road, Suite B Females are slightly smaller, weighing 14-33 kg and measuring 1-1.4m in length. Sea otters in Prince William Sound were from the original surviving 1911 population… predator prey relationship graph, The graph above shows the predator population in blue and the prey population in red – and is generated when the predator is both very aggressive (it will attack the prey very often) and also is very dependent on the prey (it can’t get food from other sources). location. However, starting in the early 1990s, Estes and his colleagues noted that otter population numbers were dropping precipitously. Recently, the southern population has grown in some measure to more than 3,000 individuals. As resources in a population become less available, population growth a. becomes negative. Fig. However depleted otter populations throughout Alaska’s Aleutian Islands still remain at 50% of their 1980 abundance. SURVEY . When you graph a population's exponential growth over time, you will have an S-shaped graph. One of the most staggering facts from this survey was that when sea otters recolonized the area in 1984, the eelgrass population increased by 600%, which definitely displays that sea otters have something to do with the population … Ventura, California 93003, Southern Sea Otter (Enhydra lutris nereis) 5-Year Review: Summary and Evaluation, Big Sur Monterey Sea Otter Study Draft Report, Letter to Deputy Assistant Secretary of the Navy Donald Schregardus FSEIS Comments, Final Supplemental EIS on the Translocation of Southern Sea Otters - Volume 1, Final Supplemental EIS on the Translocation of Southern Sea Otters - Volume 2, Final Recovery Plan for the Southern Sea Otter. Before the fur trade of the 18th and 19th centuries, sea otters ranged along the North Pacific Rim from Hokkaido, Japan to Baja California, Mexico. 2750 in 2007 - 2250 in 1997 = an increase of 500 . otter populations in WPWS annually to track the progress of sea otter recovery, except in 2001 and 2006. In Alaska, the sea otter population is higher, but declining steadily since the Exxon Valdez oil spill in 1989. and southeast Alaska (Figure 1b). 1: Recent sea otter population growth graph from the Western Ecological Research Center (2007) Differences between Moss Landing and West Cliff: Moss Landing harbor has a unique environment. Sea otters most closely resembling today’s southern sea otters occupied the southernmost portion of that range—from at least as far north as Oregon to the species’ southern limit at Punta Abreojos, Baja California. 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