These data arise from a field study of groundfish catch monitoring in Kodiak, AK trawl fisheries. Two monitoring components were included in the study: 1) at-sea sampling methods used by observers to sample species composition of catch and 2) shore-side sampling of delivered catch by observers to validate landings species composition reports. The at-sea portion of the study consisted of a side-by-side comparison (two observers) of a proposed new sampling method and the standard sampling method. Observer data were recorded at-sea on paper and transferred to an Oracle database. The shoreside component of this study consisted of observer species composition sampling in plants for later comparison with landings data. The shore-side data were collected by observers in processing plants, recorded on paper and transferred to an Oracle database. Data collection started in April 2011 and continued through August 2011. Third party landings data (NOAA Fisheries, Alaska Regional Office, Sustainable Fisheries Division) that were used in the analysis are stored in an oracle database. Data for both project components (at-sea and shoreside) were collected during normal fishing activities onboard commercial trawl catcher vessels and during normal processing activities in shore-based processing plants.