A zip package containing timestamped GPS trackpoints recorded during all sea otter aerial surveys in one year presented as one GPX-formatted XML file per survey flight. Each trackpoint reflects timestamp, atitude, longitude, and elevation. The detailed content is defined in SOP 15 of the protocol package

CSV files containing counts of GLBA sea otters and covariates derived from SO_C photos presented as one ZIP file per annual survey. The detailed content is defined in SOP 14 of the protocol package.

Counts of GLBA sea otters and covariates derived from SO_C photos used for estimating detection rates presented as a zip package containing one CSV file per aerial survey. The detailed content is defined in SOP 19 of the protocol package

Sea otter sighting data including location; point locations for the beginning and end of each transect were programmed into an aircraft global positioning system, each sea otter sighting was recorded by hand on a data sheet by the observer. Sea otter density was estimated from the aerial counts and applied to the entire study area for an estimate of population abundance. Distribution Survey: 8-9 August 1995 (Cape Suckling to Cape Spencer); 19-23 August 1996 (Cape Hinchinbrook to Cape Suckling). Abundance Survey: 7-9 August 1995 (Yakutat Bay)

The data package "Sea Otter Aerial Survey Data from Glacier Bay National Park and Preserve, 1999-2012" provides raw data for examining abundance and distribution of northern sea otters (Enhydra lutris kenyoni) in Glacier Bay National Park and Preserve in southeast Alaska, based on data collected during a series of population-wide aerial surveys. The USGS aerial sea otter surveys have been completed multiple times using consistent methodology involving aerial-based counts. The surveys provide data and a population estimate that Park and other Federal management agencies use for decision making and planning additional research. This data package includes a series of files with the raw digital data that was used for population estimates and population modeling found in related manuscripts.

Sea otters (Enhydra lutris kenyoni) are an apex consumer in the North Pacific Ocean and are known to influence and structure nearshore marine communities. Sea otters were extirpated from southeastern Alaska prior to 1911 due to the commercial fur trade; however, 413 sea otters were reintroduced to southeastern Alaska from 1965 to 1969. By 1988, sea otters had expanded into lower Glacier Bay and the U.S. Geological Survey (USGS) began aerial survey monitoring efforts to monitor the colonization, distribution, and abundance of sea otters; these efforts continued through 2012. Currently, sea otters are one of the most abundant marine mammals in the park. In 2015, sea otters were identified as a vital sign by the National Park Service’s Southeast Alaska Network (SEAN) Monitoring Program due to their role as a keystone species in the nearshore marine ecosystem. The primary objectives of the monitoring program are to use contemporary field and analytical methods to monitor the abundance and spatial distribution of sea otters in Glacier Bay. A spatio-temporal statistical model representing current knowledge of sea otter abundance and distribution, including underlying ecological processes governing colonization dynamics in Glacier Bay, was constructed using multiple sources of data collected on sea otters between 1993 and 2012 by USGS and will accommodate future data to be collected via aerial photographic surveys (Williams et al. 2017, Ecology). Contemporary methods for obtaining digital imagery and counting sea otters from the imagery were developed to replace prior observer-based methods. Aerial photographic surveys will be conducted and digital imagery will be archived as a permanent record enabling independent verification of counts of sea otters and quantification of habitat covariates. The new monitoring design implements an iterative optimal dynamic sampling scheme to increase sampling efficiency, providing the most information from the data that can be collected affordably. The spatio-temporal model will be used to generate forecasts of sea otter abundance and associated uncertainty for subsequent monitoring periods. Forecasts then will be used as a template to select a set of survey transects that minimize the uncertainty in model-based forecasts of predicted abundance of sea otters. Optimal survey designs will be updated following each year data are collected and, therefore, are dynamic through time. A set of random transects also will be selected to supplement, validate, and compare abundance estimates of sea otters among sampling approaches. Real location of effort among survey types will be considered in the future as another means to optimize program performance and efficiency. The combination of using (1) aerial photographs for collecting data, (2) advanced and flexible statistical models that incorporate our understanding of the ecological system, permitting rigorous estimates of occupancy, abundance, and colonization dynamics, and (3) a sampling framework that explicitly links our statistical model and future data to be collected will improve monitoring efficiency and our ecological understanding of sea otters in Glacier Bay.

The data are .csv files of tagged sea otter re-sighting locations (henceforth, resights) collected in the field using a combination of VHF radio telemetry and direct observation using high powered (80x) telescopes. Sea otters were tracked by shore based observers from the date of tagging until the time of radio battery failure or the animal’s death, whichever comes first. The frequency of re-sighting was opportunistic, depending on logistical factors such as coastal access, but generally ranged from daily to weekly. Location coordinates are reported as X and Y coordinates in the projection/datum California Teale-Albers NAD 1927. Each file contains resight data for one individual sea otter collected over a period of 1-10 years. Fields include individual identification number, geographic coordinates, the date and time of the sighting location, and associated behavioral state of the individual at the time of re-sighting.

These data describe observations of sea otter foraging behavior in Glacier Bay National Park and Preserve. Data consist of dive and surface times, success in prey retrieval, prey item, prey quantity, and size. Additionally, location of observations, and age class, sex, and pup status of the focal sea otter were also recorded.

This dataset consists of three tables related to abundance and distribution of northern sea otters (Enhydra lutris kenyoni) in Southeast Alaska, based on data collected during a series of population-wide aerial surveys. 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 consists of three tables related to abundance and distribution of northern sea otters (Enhydra lutris kenyoni) near the outer Kenai Peninsula, Alaska, based on data collected during a series of population-wide aerial surveys in June 2019. 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.