NOAA Technical Memorandum
NMFS-AFSC-142
Identification of skates, sculpins, and smelts by observers in North Pacific groundfish fisheries (2002-2003)
Abstract
Recent emphasis on ecosystem-level management of federally regulated marine fisheries, as well as a rapidly developing skate fishery in the Gulf of Alaska, has led to an increasing need for basic population data for skates (Rajidae), sculpins (Cottidae and allied families), and forage fishes (e.g., Osmeridae, Clupeidae, and Ammodytidae). Observers in the North Pacific Groundfish Observer Program could provide a wealth of such data by routinely identifying these fishes to the species level. The objectives of this project were 1) to quantify the additional time observers would require on a per-haul basis to complete species-level identifications of all skates and smelts, and genus-level identifications of selected sculpins; and 2) to develop and assess the adequacy of an introductory training presentation and a series of materials for use by observers in the field.
Over 130 returning fisheries observers were trained to identify skates, smelts, and sculpins. Once deployed, participating observers established an alternating sampling scheme of control hauls and experimental hauls. Participants completed Species Identification forms for each new species encountered and recorded species composition data in the NORPAC database. After deployment, debriefers solicited comments and constructive feedback from participants and assessed the accuracy of field identifications.
Participating observers required an average of 4.27 additional minutes per haul to complete the specific identifications. The time required was not dependent on the gear used or target of the fishery, but variation among observers and among hauls within cruise was substantial. The field identification resources and training presentation were constantly updated throughout this study to reflect participant feedback and new information. Participants were usually able to demonstrate confident knowledge of identifications during debriefings, and geographic and bathymetric distributions obtained from study data generally did not conflict with published distributions or those obtained from bottom trawl survey data. Therefore, there were no indications of any widespread identification problems in this study.
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