This reduced survival led to chronic losses of; 900 animals over the past two decades, which is similar in magnitude to the number of sea otter deaths documented in western Prince William Sound during the acute phase of the spill. Often data can be collected easily, and they usually reflect current environmental conditions for assessing human-induced changes in the environment. Elevated mortality is the most likely reason for this depressed population growth rate; however, the cause or causes of elevated mortality remain unclear, The USGS, Alaska Science Center's Nearshore Marine Ecosystem Research program (https://www.usgs.gov/centers/asc/science/nearshore-marine-ecosystem-research?qt-science_center_objects=0#qt-science_ce, The goal of the Gulf Watch Project (https://gulfwatchalaska.org/monitoring/nearshore-ecosystems/) includes monitoring a wide variety of species inhabiting the nearshore system. By employing a spatial design that allows broad geographic inference and selecting species with direct food web linkages, our monitoring program simultaneously detects change and assesses potential mechanisms underlying that change. We hypothesize that the patchy nature of residual oil left in the environment has created a source-sink population dynamic. ... Ainley DG, Sydeman WJ, Hatch S, Wilson U (1994) Seabird population trends along the west coast of North America: Causes and the extent of regional concordance. The translocation and subsequent population growth and range expansion of the northern sea otter (Enhydra lutris kenyoni) in Washington State over the last five decades has created a spatio‐temporal gradient in sea otter occupation time and density, and acts as a natural experiment to quantify how sea otter population status and habitat type influence sea otter diet. Initial research efforts following the spill focused on damage assessment, including developing methods to accurately estimate the abundance of affected populations and studies of reproduction and survival. We have a one-dimensional coastline in California as compared to the two-dimensional coastlines of much of Alaska. The effects of sea otters (Enhydra lutris) on abalone (Haliotis spp.) As mammals, sea otters have hair and feed their babies milk. food chains and web's worksheets, coral reef community coloring pages and ocean coral reef coloring page are three main things we want to present to you based on the. Our models resulted in hind-cast (1989-2003) predictions of net population growth and range expansion that closely matched observed patterns. The recovery of sea otters to ecosystems from which they had been absent has affected coastal food webs, including commercially important fisheries, and thus information on expected growth and equilibrium abundances can help inform resource management. Which populations were wiped out, and in what order? The fundamental force behind population change is the balance between age-specific survival and reproductive rates. The status of a population is expressed in terms of the population level as a fraction of the mean of natural (undisturbed ecosystem) equilibrium level. The GIS shapefile "Census summary of southern sea otter 2018" provides a standardized tool for examining spatial patterns in abundance and demographic trends of the southern sea otter (Enhydra lutris nereis), based on data collected during the spring 2018 range-wide census. The results of this study indicate an improved overall health of sea otters over the period of decline and suggest that limited nutritional resources were not the cause of the observed reduced population abundance. At the regional scale, the population increased from 13,221 otters in 2003 to 25,584 otters in 2011. Sea Otter Coloring Sheet - Northern Sea Otter (PDF) ... and utilizing a variety of methodological and analytical tools to understand the causes of biological and ecological trends in sea otter populations, and to predict the ecological consequences of management practices on these populations and their ecosystems. As a result, populations of sea otters in the Aleutian Islands have declined from an estimated 60,000 animals in the mid-1980s to under 10,000 by 2000. Asymptotic values of body mass were 12-18% higher in the 1990s than in the 1960s/70s, and asymptotic values for body length were 10-11% higher between the same periods. Northern sea otters (Enhydra lutris kenyoni) are experiencing rapid population growth and expansion in Southeast Alaska. In addition, the populations of seals and sea lions and underwater ‘forests’ of kelp are disappearing. Otters do not have blubber like other marine mammals, such as whales. Our approach provides guidance for the acquisition of further data and a means of forecasting the consequence of specific management actions. Once containing more than half of the world’s sea otters, this population segment, which ranges from Kodiak Island through the western Aleutian Islands, has undergone an overall population decline of at least 55–67 percent since the mid-1980s. Sea otters come from the northern part of the Pacific Ocean, where it is very cold. Population age structures differed significantly between the 1960s/70s and the 1990s with the latter distribution skewed toward younger age classes (indicating an altered lx function) suggesting almost complete relaxation of age-dependent mortality patterns (i.e. 12, Affiliation: U.S. sea otters in the past, but now consumes thousands of otters. Currently, the program evaluates six ecological indicators and more than 200 species that range from primary producers to top level consumers and is designed to examine both bottom-up and top-down dynamics. Standard length of mature otters (asymptotic size = 148.2±2.9cm [SE]) was greater than previous studies in Alaska. those typical of food-limited populations). 3. Our results suggest that residual oil can affect wildlife populations on time scales much longer than previously believed and that cumulative chronic effects can be as significant as acute effects. Much of our knowledge of the role of sea otters as a source of community variation resulted from the spatial and temporal pattern of sea otter population recovery since their near extirpation about 100 years ago. With the exception of 13 small remnant populations, sea otters were extirpated from their historic range in the north Pacific Ocean during the 18th and 19th centuries as a result of the commercial harvest for their fur. oil spill response planning documents and provide interagency reviews as well as testimony at public meetings. Here we fit time-varying population models to data for the sea otter population of western Prince William Sound to quantify the duration and extent of mortality effects from the spill. Local populations vary in terms of current densities and expected future growth; the mean estimated density at K was 4.2 ± 1.58 sea otters/km2 of habitat (i.e., the sub‐tidal benthos between 0 m and 40 m depth) and current densities correspond on average to 50% of projected equilibrium values (range = 1–97%) with the earliest‐colonized sub‐regions tending to be closer to K. Assuming a similar range of equilibrium densities for currently un‐occupied habitats, the projected value of K for all of Southeast Alaska is 74,650 sea otters. The historic or natural carrying capacity of disturbed ecosystems can not be directly assessed. They often rest in coastal kelp forests, draping the kelp over their bodies to keep from drifting away. We found that TDRs provided data useful for measuring activity time budgets and behavior patterns in a diving mammal over long and continuous time periods. Undertake research that will facilitate and enhance recovery efforts .....57 7. Estimates of acute spill related mortality range from about 1,000 to 5,500 in the first months after the spill. Levels for total PCBs in Aleutian otters (310 μg/kg) were 1.7 times higher than levels in California otters (190 μg/kg) and 38 times higher than otters from southeast Alaska (8 μg/kg). Long term continuation of studies investigating mortality from the annual collections of beach cast sea otter carcasses implicates elevated mortality as the factor contributing to delayed recovery, and suggests that chronic mortality after the spill meet or exceeded the acute mortality experienced after the spill. The nearshore ecosys, Sea otters were severely impacted by the 1989 Exxon Valdez oil spill. Using demography and movement behavior to predict range expansion of the Southern Sea Otter, Activity Budgets Derived From Time‐Depth Recorders in a Diving Mammal. Animals in this study reached sexual maturity earlier than previous studies, at age 3–4 years. The student measured the kelp abundance at 4 different sites, then spent a day at each site and marked whether otters were present or absent every 5 minutes during daylight hours. Quantitative models of range expansion have rarely been applied to large vertebrates, although such tools could be useful for restoration and management of many threatened but recovering populations. Although wild animal populations always rise and fall to some degree, a decline of this size cried out to be explained. Habitat characteristics are primary determinants of nearshore marine communities. © 2008-2021 ResearchGate GmbH. For the population stocks listed under the Endangered Species Act we produce recovery plans, determine critical habitat and review listing status. Contacts: Julie Yee, Brian B Hatfield, Joseph Tomoleoni. Growth curves demonstrated a significant increase in body mass and body length at age in the 1990s. the Alaska Science Center were among the first responders to the 1989 spill and continue work today to document the process of recovery form this spill and to better understand the effects future contamination events on sea otters and the nearshore ecosystems they occupy. Biochemical and gene techniques suggested that lingering oil may have contributed to a protracted recovery period for nearshore species. We are using this situation in Glacier Bay as a laboratory to experimentally evaluate the role of sea otter in structuring coastal marine communities in a predominately soft sediment habitat. 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