Seals, polar bears, and polar bear track counts were summarized from U.S. and Russian survey flights over the Chukchi Sea during aerial surveys in April and May of 2016. Seal detections were made using using infrared imagery, with corresponding digital photographs providing information on species identification, where possible. Polar bear detections were made using a variety of methods, including infrared (thermal) detections, in situ observations by human observers, and through post hoc searching of photographs. These observations are summarized within a discretized study area, where grid cells are approximately 625 km^2, with the intention of estimating the distribution and abundance of all three species (bearded seals, Erignathus barbatus; ringed seals, Pusa hispida; and polar bears, Ursus maritimus). Data are provided in 5 .csv (comma delimited text) files, summarizing (1) the location of grid cells, and some associated environmental and physiographic covariates (CHESS_grid_axiom.csv), (2) survey effort per grid cell in U.S. airspace, including counts of seals and information on polar bear tracks (effort_us.csv), (3) survey effort per grid cell in Russian airspace, including counts of seals and polar bear tracks (effort_russia.csv), (4) locations, group sizes, and detection types for polar bear groups encountered in surveys within U.S. airspace (pb_encounters_us.csv), and (5) locations, group sizes, and horizontal distances for polar bear groups detected in surveys over Russian airspace. Owing to differences in detection methods for polar bears, we advocate using a distance sampling approach for analyzing Russian polar bear detections, and a strip transect approach to analyzing seal and U.S. polar bear detections.

This dataset consists of around 80,000 color and IR (thermal) images, associated with flights conducted in Alaska by the NOAA Alaska Fisheries Science Center in 2019. Images have been annotated with around 28,000 bounding boxes (14,000 on color images, 14,000 on thermal images) on ice seals.

The top five maximum ages encountered by the AFSC Age and Growth Program for collections aged between 1990 and 2020 except Pacific cod, which is limited to collections read after 2000.

Maximum age data is from ages generated between 1990 and 2020 except Pacific cod, which is limited to collections read after 2000.

Natural mortality (M) is estimated using the method outlined by Hoenig (1983) which uses maximum age to estimate instantaneous mortality.

Experimental apparent optical properties data product for the eastern Bering Sea

Description:
This zip file contains a sample of an experimental apparent optical properties data product for the eastern Bering Sea, derived from light measurements collected during a 2004 bottom-trawl survey conducted by NMFS/NOAA. The full experimental data product includes

For additional years of data (2004–2019), contact Sean K. Rohan .

A description of fields in the experimental data product and methods used to derive the data product are provided in the references below.

References:
Rohan, S. 2020. trawllight: derive apparent optical properties from trawl-mounted light sensors. doi: 10.5281/zenodo.2567237.
Rohan, S., Kotwicki, S., Britt, L., Laman, E., Aydin, K. In prep. Deriving apparent optical properties from light measurements obtained using bottom-trawl-mounted archival tags. NOAA Technical Memorandum. AFSC-XX-XX