The data consist of blood chemistry and hematology from sea otters captured at sites along the Aleutian archipelago, the Alaska Peninsula, the Gulf of Alaska, and Prince William sound between 2004 and 2012. The data include the blood chemistry and hematology findings as well as general capture location, if the sea otter population in that area is declining, capture date, age estimate, age class, sex, and a unique sea otter number connecting the sample to gene expression data.

Three data sets are included here to aid in assessment of the sea otter population collapse in southwest Alaska. One data set consists of results of sea otter surveys conducted between 1959 and 2015 at Bering Island, Russia and a selection of western Aleutian Islands in Alaska. Sea otter counts are reduced to a comparable value of otters per linear kilometer. Another data set consists per-capita and per kilometer recovery rates of stranded sea otter carcasses from locations ranging from Bering Island, Russia, several Aleutian Islands, sites along the Alaska Peninsula, and Prince William Sound, Alaska. These data are mainly from the period 1991-2009 and are from stable populations as well as those in decline or post decline. The third data set consists of blood chemistry and hematology of sea otters captured from along this same north Pacific region from 2004-2012. This data set can be used to help assess sea otter health in this region. Gene transcription data from some of the subject sea otters can be found at Bowen, L., Ballachey, B. E., Bodkin, J. L., Miles, A. K., Esler, D. and Kloecker, K. A., 2017, Sea Otter Gene Transcription Data from Kodiak, the Alaska Peninsula, and Prince William Sound, Alaska, 2005-2012: U.S. Geological Survey data release, https://doi.org/10.5066/F789141P. These data support the following publication: M. Tim Tinker, James L. Bodkin, Lizabeth Bowen, Brenda Ballachey, Gena Bentall, Alexander Burdin, Heather Coletti, George Esslinger, Brian B. Hatfield, Michael C. Kenner, Kimberly Kloecker, Brenda Konar, A. Keith Miles, Daniel H. Monson, Michael J. Murray, Ben Weitzman and James A. Estes, 2021, Sea otter population collapse in southwest Alaska: assessing ecological covariates, consequences, and causal factors: Ecological Monographs

This data set includes capture location, date, sex, and results of molecular gene transcription analysis for sea otters (Enhydra lutris) sampled in western Prince William Sound (WPWS), Alaska and comparison samples collected from Kodiak and the Alaska Peninsula, and reference samples collected from captive animals. Samples were collected between 2005 and 2012. (Molecular gene transcription is the process by which information from the DNA template of a particular gene is transcribed into messenger RNA (mRNA) and eventually translated into a functional protein. The amount of mRNA transcribed from a particular gene is physiologically dictated. Altered levels of gene transcripts provide observable signs of health impairment.)

The data consist of levels of organic pollutants found in the blood of sea otters captured from five areas in the western Aleutian Islands and in Cross Sound in southeast Alaska. For each location, the sample size, and the median and range of values for each compound is provided. The compounds are PCBs (polychlorinated biphenyls), DDTs (dichlorodiphenyltrichloroethanes), HCHs (hexachlorocyclohexanes), chlordane, HCB (hexachlorocyclobenzene), and dieldrin.

The table presents summary data of sea otter skulls found on carcass searches conducted along stretches of shoreline at islands or locations along a longitudinal span encompassing the sea otter population decline. Numbers of skulls encountered, length of shoreline searched, population density calculated from survey data, as well as skulls per kilometer and per-capita recovery rate are presented. The data are arranged in west to east order from Bering Island to Prince William Sound.

This dataset consists of three tables related to abundance and distribution of northern sea otters (Enhydra lutris kenyoni) in northern and eastern Prince William Sound, Alaska, based on data collected during a series of population-wide aerial surveys in June 2014. The dataset consists of: (1) sea otter counts along strip transects, (2) sea otter counts in Intensive Search Unit (ISU) within the transects, and (3) Transect coordinates.

This dataset includes morphometric measurements and pregnancy / dependency status from sea otters captured or collected (experimental harvests or recovered after the Exxon Valdez Oil Spill) in Alaska, 1947-2019 by the U.S. Geological Survey (USGS) and the U.S. Fish and Wildlife Service (USFWS). Data collected include total body length, tail length, body mass, axillary girth, paw width, canine diameter and baculum length along with sex, age, and reproductive status of females (pregnancy / dependency status). For females with dependent pups, pup sex, mass, and total length are included when available. For harvested animals, data includes pregnancy status along with fetal sex, mass, and length.

The data table consists of a compilation of sea otter survey results from Bering Island, Russia and select Western Aleutian Islands conducted between 1959 and 2015. The counts were reduced to sea otters per kilometer of coastline for temporal comparability. A correction factor of 3.6 was applied to aerial survey totals to yield results comparable to skiff based surveys. The data table provides the island, year, mode (aerial, skiff, or ground), and shore length covered in each survey. Counts of independent otters and pups are provided if available. Total otters counted or calculated with the correction factor and the calculated linear density are also provided.

Two data sets concerning organic contaminants are included here to aid in assessment of the sea otter population collapse in southwest Alaska. One data set consists of levels of organic pollutant compounds found in wild sea otter blood collected from captured animals in 1997 (Jessup et al., 2010). These sea otters were captured from islands in the western Aleutians and from outside the area of population collapse, in southeast Alaska near Cross Sound. Another data set consists of levels of organic pollutant compounds found in blue mussels collected from multiple sites along the Aleutian archipelago and from the Cross Sound area in southeast Alaska in 1994-1996 (Reese et al., 2012). These data support the following publication: M. Tim Tinker, James L. Bodkin, Lizabeth Bowen, Brenda Ballachey, Gena Bentall, Alexander Burdin, Heather Coletti, George Esslinger, Brian B. Hatfield, Michael C. Kenner, Kimberly Kloecker, Brenda Konar, A. Keith Miles, Daniel H. Monson, Michael J. Murray, Ben Weitzman and James A. Estes, 2021, Sea otter population collapse in southwest Alaska: assessing ecological covariates, consequences, and causal factors: Ecological Monographs References: Jessup, D. A., C. K. Johnson, J. Estes, D. Carlson-Bremer, W. M. Jarman, S. Reese, E. Dodd, M. T. Tinker, and M. H. Ziccardi. 2010. Persistent organic pollutants in the blood of free-ranging sea otters (Enhydra Lutris Ssp.) in Alaska and California. Journal of Wildlife Diseases 46:1214-1233. Reese, S. L., J. A. Estes, and W. M. Jarman. 2012. Organochlorine contaminants in coastal marine ecosystems of southern Alaska: inferences from spatial patterns in blue mussels (Mytilus trossulus). Chemosphere 88:873-880.

This dataset consists of three tables related to abundance and distribution of northern sea otters (Enhydra lutris kenyoni) in western Prince William Sound, Alaska, based on data collected during a series of population-wide aerial surveys in June 2017. The dataset consists of: (1) sea otter counts along strip transects, (2) sea otter counts in Intensive Search Unit (ISU) within the transects, and (3) Transect coordinates.