Fish and invertebrates that are unintentionally captured during commercial fishing operations and then released back into the ocean suffer mortality at unknown rates, introducing uncertainty into the fishery management process. Attempts have been made to quantify discard mortality rates using reflex action mortality predictors or RAMP which use the presence or absence of a suite of reflexes to predict discard mortality. This method was applied to Tanner crab, Chionoecetes bairdi, during the 2010-2012 fisheries in the Bering Sea. Discard mortality in the fishery is currently assumed to be 50% in stock assessment models, but that rate is not based on empirical data and is widely recognized to be in need of refinement. Over 19,000 crab were evaluated using the RAMP method. The estimated discard mortality rate was 4.5% (SD = 0.812), significantly below the rate used in stock assessment models. Predicted discard mortality rates from the 2010-2012 study were strongly correlated with the air temperature at the St. Paul Island airport in the Pribilof Islands. Using this relationship the discard mortality rate from 1991-2011was estimated at 4.2% (SD = 1.08).

The potential for unobserved mortality of crabs encountering bottom trawls, but not captured, has long been a concern in the management of Bering Sea fisheries. We evaluated how many such crabs die, including snow, Tanner and red king crabs, and demonstrated changes to trawl gear that substantially improved crab survival.

This dataset contains detailed crab data collected from the 2012 NOAA/NMFS/AFSC/RACE crab-groundfish bottom trawl survey of the Chukchi Sea. 71 survey stations were successfully completed during the bottom trawl survey. The survey area extended north and east from the Bering Strait to Barrow Canyon, bounded to the west by the U.S.-Russia Maritime Boundary and east to the 10-m bathymetry limit along the Alaska coastline. Demersal populations were sampled by trawling at stations centered within 55.56 x 55.56 km (30 x 30 nautical miles) grid cells covering the survey area. 100% of the catch is sorted for commercially important crab species. Crabs are sorted by species and sex, and a sample is measured to the nearest millimeter to provide a size-frequency distribution (see note under use constraints for analyzing catches where crab were subsampled for measurement). Carapace width is measured for Tanner crabs, and carapace length is measured for king and hair crabs.

The Resource Assessment and Conservation Engineering Division (RACE) of the Alaska Fisheries Science Center (AFSC) conducts bottom trawl surveys to monitor the condition of the demersal fish and crab stocks of Alaska. These data include catch per unit effort for each commercially important crab species at a standard set of stations in the eastern Bering Sea. This is a subset of the main database. Excluded are certain non standard tows and other types of data collected other than species id, species size category, species catch per unit effort (number per square nautical mile), water temperature and depth.

This dataset contains data from a series of experiments that determined the upper thermal tolerance of early benthic stage red and blue king crabs. Experiments included determining the temperature at which 50% of crabs died after 24 hour exposure, determining the effect of temperature on feeding ration, and the effects of temperature on long-term growth and mortality.

This dataset contains detailed crab data collected from the annual NOAA/NMFS/AFSC/RACE crab-groundfish bottom trawl survey of the eastern Bering Sea continental shelf. The standard survey area, surveyed each year since 1975, encompasses a major portion of the eastern Bering Sea shelf between the 20 meter and 200 meter isobaths and from the Alaska Peninsula to the north of St. Matthew Island. The study area is divided into a grid with cell sizes of 20 x 20 nautical miles (37 x 37 kilometers). Sampling takes place within each 20 x 20 nautical mile grid cell. In areas surrounding St. Matthew (1983-present) and the Pribilof Islands (1981-present), grid corners were also sampled to better assess king crab concentrations. In 1975, tows were 1 hour in duration; from 1976 to present, each tow is one-half hour in duration, averaging 1.54 nautical miles (2.86 kilometers) - exact tow duration and distance fished for each haul can be found in RACEBASE.HAUL. 100% of the catch is sorted for red, blue, and golden king crab, bairdi Tanner, snow crab, hybrid Tanner, and hair crab. Crabs are sorted by species and sex, and a sample is measured to the nearest millimeter to provide a size-frequency distribution (see note under use constraints for analyzing catches where crab were subsampled for measurement). Carapace width is measured for Tanner crabs, and carapace length is measured for king and hair crabs.

Seasonal migration of commercial-size (=102 mm carapace width [CW]), morphometrically mature (MM) snow crabs (Chionoecetes opilio) from the eastern Bering Sea was examined in relation to the summer distribution of mature females to identify spatiotemporal overlap of males and females and determine the likelihood of mating associations for specific reproductive stages. Depth variation associated with this migration was examined to determine whether seasonal migrations contribute to previously recognized spatial differences in distributions of commercial-size males caught in the winter fishery and in the National Marine Fisheries Service summer bottom trawl survey. Depth data from 33 data storage tags attached to commercial-size MM males during 2010 and 2011 indicated that most males moved inshore during spring—a movement that would allow them to mate with multiparous females but not with pubescent-primiparous females. Smaller tagged males (100–102 mm CW) underwent more extensive inshore migrations, and several of them traveled more than 100 km in one direction. Both tagging and distribution data indicated that most commercial-size MM males remained predominantly on the outer shelf throughout the year (despite some inshore movements during spring) and, therefore, these males did not contribute greatly to the spatial differences observed between winter and summer.

Economic data collected for years 1998, 2001, 2004, and 2005 and onward for the BSAI Crab Economic Data Report (EDR). Reporting is required of any owner or leaseholder of a vessel or processing plant, or a holder of a registered crab receiver permit, that harvested, processed, custom processed, or obtained custom processing for rationalized crab in specified Bering Sea and Aleutian Islands (BSAI) crab fisheries during the prior calendar year.

Polar Ecosystems Program research projects focus primarily on abundance, trends, distribution, health and condition, and foraging behavior of phocids (harbor, bearded, ringed, spotted, and ribbon seals) in Alaska. This database contains health and disease data obtained by analysis of different blood parameters, molecular analysis of swabs, stable isotope analysis, and contaminant analysis from seals across a variety of research projects. Biological samples (e.g. blood, tissue, hair, nasal swabs, and whiskers) have been collected from ribbon and spotted seals in the Bering Sea, bearded seals in the Bering and Chukchi Seas, and harbor seals in the north Pacific and Bering Sea. Ribbon seal samples were collected in 2005-2010, 2014; spotted seal samples were collected in 2005-2010, 2014; bearded seal samples were collected in 2007, 2009, 2011, 2012, 2014; ringed seal samples were collected in 2007-2009; harbor seal samples were collected in 2004-2006, 2012.

Since 1988, scientists at the Auke Bay Laboratories have been using the /Delta/ submarine for a wide range of research projects. Over 500 dives have been completed. The video collected during these projects provides valuable direct observations of seafloor habitat and biological attributes. This project is assembling a database that will include dive locations and basic biological and substrate information from each of the dives. To date, biological and substrate data have been processed for about 40% of the dives.