Spatial Data Collected by Groundfish Observers in Alaska

May 09, 2018

This system is designed to provide visitors a tool to better understand where fish and invertebrates are caught in the Bering Sea/Aleutian Islands (BSAI) and Gulf of Alaska (GOA) groundfish fisheries by examining data collected by observers.

The underlying information for these maps comes from a database of observer samples maintained by the Fisheries Monitoring and Analysis (FMA) Division of the Alaska Fisheries Science Center. Information collected by observers, together with catch and production reports submitted by the fishing industry, provide the basis for estimating overall catches from the GOA and BSAI. The portion of the catch sampled by observers varies by region, vessel-type, gear-type, and target fishery. Since 2001, vessels with observers in the BSAI have accounted for approximately 90% of the groundfish tonnage caught and observers have sampled the catch from about three-fourths of the hauls/sets. Vessels with observers in the GOA have accounted for approximately 40% of the groundfish tonnage caught and observers have sampled the catch from about two-thirds of the hauls/sets.

Since all fishing operations are not observed, neither the maps nor the data can be used to characterize the fisheries completely. Furthermore, estimates of the composition of observed catches or sets are generally determined by expanding sample catch compositions recorded by observers. These maps present aggregate catch composition only from observed hauls and sets and expanded as described above and will not always provide an accurate portrayal of catches of target and non-target species by the whole fleet. Inaccuracies will be greatest for rarely-occurring species and when sample sizes are relatively small. We caution users about making simple expansions from these data because of the complexity of the groundfish fisheries and the fleets which harvest them.

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Last updated by Alaska Fisheries Science Center on 10/30/2019

Alaska Groundfish Research Fisheries Monitoring and Analysis North Pacific Observer Program