Data Management Plan

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.

Process Steps:

• Data were entered into a spreadsheet and converted to point features in ArcGIS.
• Point features were converted to line features based on feature and vertex ID to represent the starting and ending locations of each trawl deployment. Catch and other environmental data, such as depth and temperature, were then spatially joined to each line segment based on a key field identifier from the original data.
• 1996-08-01 00:00:00 - Macrofauna sampling was conducted aboard two identical 40 m chartered stern trawlers, the sister ships FV ??Aldebaran?? and FV ??Arcturus??. Each is powered by a 1525 hp main engine and fitted with a variable pitch propeller and propeller nozzle. Macrofauna were sampled with identical 83?112 eastern otter trawls, selected to ensure relatively large samples of patchily distributed organisms and to minimize clogging of the opening by large macrofauna (e.g. sea stars). These nets have a 25.3 m headrope and a 34.1 m footrope and have been the standard sampling gear used for annual NMFS groundfish-crab surveys in the EBS since 1982. The trawl was towed behind 1000 kg steel V-doors and 54.9 m paired dandylines. Each lower dandyline has a 0.61 m chain extension connected to the lower wing edge to improve bottom-tending characteristics. For this study, the standard trawl was modified to improve catchability and retention of macrofauna. It was equipped with a tickler chain and a hula skirt, and had a 3.8 cm liner covering both wings and the entire bottom body, with complete coverage top and bottom of the intermediate and codend. An acoustic net mensuration system and a mechanical bottom contact sensor were used to assess net configuration and collect performance data for area-swept and catch-per-uniteffort (c.p.u.e.) calculations. Each vessel sampled adjoining HF-UF stations (??pairs??) by towing the trawl through the centre of a 1 nm2 cell for 1.39 km (i.e., 3 knots for 15 min). Catches were fully processed in the field by sorting macrofauna to the lowest possible taxon and then weighed and enumerated separately. Weights were determined using a motion-compensated precision electronic balance. Biogenic substrate, such as empty gastropod and bivalve shells, and identifiable egg masses were also weighed, so as to provide a more complete characterization of the benthos. Prior to analysis, catch data were lumped into larger taxonomic groups to resolve classification differences between the vessels and to reduce the number of dependent variables. Bottom trawl catches (CPUE)are standardized according to area swept, as determined with Scanmar ascoustic system and GPS coordinates of vessel. Catch values are counts of organisms/hectare.

see Process Steps

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IT Security and Contingency Plan for the system establishes procedures and applies to the functions, operations, and resources necessary to recover and restore data as hosted in the Western Regional Support Center in Seattle, Washington, following a disruption.