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 snow crab, Chionoecetes opilio, 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).

These are data from a laboratory experiment in which wild caught male Tanner crab (Chionoecetes bairdi) from Stephens Passage, SE Alaska were held to evaluate crab survival while harboring Hematodinium sp., a parasitic dinoflagellate and causative agent of Bitter Crab Syndrome (BCS). In October 2014, Tanner crab in various condition states were targeted and collected. Targeted crab condition states were visually healthy, visually BCS positive or questionably BCS positive. Crab were held from capture until death (ongoing) and crab were tested regularly for parasite presence using two methods, blood smears and a PCR assay to detect the presence of parasite DNA. The data include crab morphometrics, disease status by diagnostic method, and crab survival duration.

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.

This dataset is part of a laboratory experiment, which evaluated how varying prey densities (year-0 blue king crabs) and habitat type (shell and sand) affect the functional response of year-1 blue king crabs, crypsis of prey crabs, and foraging behavior of predator crabs. The data includes date, experimental duration, tank number, predator species, prey species, predator size, substrate type, initial and final prey densities, number of prey eaten, crypsis indices, survival, and time spent foraging.

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.

Rearing crustaceans communally for aquaculture, stock enhancement or research often results in high rates of cannibalism and low yields. One potential strategy to reduce loss from cannibalism is to rear crustaceans in individual cells. As small holding cell size can result in decreased growth or increased mortality, it is essential to identify the optimal holding cell size, both for mass culturing efforts and for experimental design purposes. In this study, we reared juvenile red king crab, Paralithodes camtschaticus, (3.67 to 8.30 mm carapace length) in 20, 40, and 77 mm diameter holding cells and monitored growth and survival over a 274-day experiment.