The eastern Bering Sea has experienced rapid and intensive development of commercial trawl fisheries. Because of good record keeping and the relatively brief history of fishing it is possible to reconstruct the spatial and temporal patterns of exploitation. Previously unfished (UF) areas can be identified and directly compared with heavily fished (HF) areas to investigate long-term consequences for the benthos. Using this approach, macrofauna populations in a shallow (48 m average) soft-bottom area were studied during 1996. Catch data were extracted from the AFSC NORPAC database for years 1973-2001 to provide a summary of trawl catch effort, specific focus was placed on the area within Fisheries Management Area 512. Data were merged with a 1nm grid that covered fisheries management area 512. The total number of hauls were summed for all points falling within each 1nm cell.

The eastern Bering Sea has experienced rapid and intensive development of commercial trawl fisheries. Because of good record keeping and the relatively brief history of fishing it is possible to reconstruct the spatial and temporal patterns of exploitation. Previously unfished (UF) areas can be identified and directly compared with heavily fished (HF) areas to investigate long-term consequences for the benthos. Using this approach, macrofauna populations in a shallow (48 m average) soft-bottom area were studied during 1996.

The eastern Bering Sea has experienced rapid and intensive development of commercial trawl fisheries. Because of good record keeping and the relatively brief history of fishing it is possible to reconstruct the spatial and temporal patterns of exploitation. Previously unfished (UF) areas can be identified and directly compared with heavily fished (HF) areas to investigate long-term consequences for the benthos. Using this approach, macrofauna populations in a shallow (48 m average) soft-bottom area were studied during 1996. Catch data were extracted from the AFSC NORPAC database for years 1973-2001 to provide a summary of trawl catch effort, specific focus was placed on the area within Fisheries Management Area 512. The total number of hauls and tonnage for each data point are provided. Foreign, domestic, and Joint Venture fishing vessels are also described.

The eastern Bering Sea has experienced rapid and intensive development of commercial trawl fisheries. Because of good record keeping and the relatively brief history of fishing it is possible to reconstruct the spatial and temporal patterns of exploitation. Previously unfished (UF) areas can be identified and directly compared with heavily fished (HF) areas to investigate long-term consequences for the benthos. Using this approach, macrofauna populations in a shallow (48 m average) soft-bottom area were studied during 1996. Catch data were extracted from the AFSC NORPAC database for years 1973-2001 to provide a summary of trawl catch effort, specific focus was placed on the area within Fisheries Management Area 512. The total number of hauls and tonnage for each data point are provided. Foreign, domestic, and Joint Venture fishing vessels are also described.

The eastern Bering Sea has experienced rapid and intensive development of commercial trawl fisheries. Because of good record keeping and the relatively brief history of fishing it is possible to reconstruct the spatial and temporal patterns of exploitation. Previously unfished (UF) areas can be identified and directly compared with heavily fished (HF) areas to investigate long-term consequences for the benthos. Using this approach, macrofauna populations in a shallow (48 m average) soft-bottom area were studied during 1996. Catch data were extracted from the AFSC NORPAC database for years 1973-2001 to provide a summary of trawl catch effort, specific focus was placed on the area within Fisheries Management Area 512. The total number of hauls and tonnage for each data point are provided. Foreign, domestic, and Joint Venture fishing vessels are also described.

The eastern Bering Sea has experienced rapid and intensive development of commercial trawl fisheries. Because of good record keeping and the relatively brief history of fishing it is possible to reconstruct the spatial and temporal patterns of exploitation. Previously unfished (UF) areas can be identified and directly compared with heavily fished (HF) areas to investigate long-term consequences for the benthos. Using this approach, macrofauna populations in a shallow (48 m average) soft-bottom area were studied during 1996. Catch data were extracted from the AFSC NORPAC database for years 1973-2001 to provide a summary of trawl catch effort, specific focus was placed on the area within Fisheries Management Area 512. The total number of hauls and tonnage for each data point are provided. Foreign, domestic, and Joint Venture fishing vessels are also described.

Benthic communities are structured by dynamically interacting factors that determine habitat quality. Since benthic macrofauna demonstrate strong and often narrowly defined affinities, forces altering (or disturbing) the environment will be of considerable importance to their distribution and abundance. Commercial fishing with mobile gear, such as bottom trawls and dredges, and the physical disturbance that results, is widespread in continental shelf areas. Because of its prevalence and the potential for adverse effects, there have been numerous attempts to quantify sea-floor exposure at various spatial scales. The well documented development of commerical fisheries in the eastern Bering Sea (EBS) since 1954 presents a unique opportunity for studying trawling impacts. The Crab and Halibut Protection Zone 1 (CHPZ1; also known as management area 512), located north of the Alaska Peninsula in Bristol Bay, has a long and complex history of trawl prohibitions that extend from 1959 to the present. Using detailed accounts of closures and fishing activity, it is possible to reconstruct historical effort and identify essentially pristine areas immediately adjacent to areas that have been heavily fished with bottom trawls. This physical arrangement permits an examination of chronic disturbance by bottom trawls, without confounding environmental effects that result from geographic separation. Sampling locations were preselected on the basis of historical fish effort. Starting positions for commercial bottom trawls (n=392 743 through July 1996) were spatially joined with a 1 nm2 grid to calculate total number of trawls per nm2, and thus identify heavily fished (HF) and unfished (UF) areas along the boundary of the CHPZ1 (NORPAC fishery observer database maintained at the NMFS Alaska Fisheries ScienceCenter, Seattle, Washington). HF and UF cells on opposite sides of the boundary line were paired a priori on the basis of spatial proximity and were generally separated by 1 nm to allow for prior navigational discrepancies. A total of 42 pairs was identified at the northeastern corner of the CHPZ1. In 1997, 54 grab samples were obtained using a 0.05 m^2 Sutar van Veen (SvV) sampler deployed from the FV Golden Dawn at many, but not all, of the paired sites in the sandy, high-current northeast corner of management area 512. An additional 28 grabs were acquired in the central region of management area 512 as part of a completely different BACI project while sampling protocols were being ironed out in the early stages of the effort. This point file contains the weights (g) of various infauna obtained from 83 grab samples.

Side-scan sonar images were collected using a Klein 2000 system and a 100/500-kHz towed ?sh that also contained a 3.5-kHz pro?ler source. A shipboard fathometer re- cording system was inoperable during the survey. The side-scan data were recorded digitally at a 10-kHz sample rate over a swath width of 100 m. Six swaths of 100-kHz data were anamorphosed, filtered, overlaid and projected to produce a spatially correct, georeferenced image of the seafloor with pixel resolution of 80 cm.

Side-scan sonar images were collected using a Klein 2000 system and a 100/500-kHz towed ?sh that also contained a 3.5-kHz pro?ler source. A shipboard fathometer re- cording system was inoperable during the survey. The side-scan data were recorded digitally at a 10-kHz sample rate over a swath width of 100 m. Six swaths of 100-kHz data were anamorphosed, filtered, overlaid and projected to produce a spatially correct, georeferenced image of the seafloor with pixel resolution of 40 cm.

The GOA/AI Bottom Trawl Estimate database contains abundance estimates for the Alaska Biennial Bottom Trawl Surveys conducted in the Gulf of Alaska and the Aleutian Islands in alternate years. The estimates build upon raw and summary data available from the RACEBASE database and include calculated catch-per-unit-effort (cpue)s for principal species of groundfish and key invertebrates for each survey region. The cpues are averaged by survey strata, and then average cpues are multiplied by stratum areas which results in estimates of biomass and numerical abundance. Length and age data are combined with abundance to estimate the population at length and sex and population at age and sex.