European Ocean Biodiversity Information System

The Baltic International Bottom Trawl Survey Database (BITS) includes research vessel data from national fishery laboratories around the Baltic Sea from 1991 until present. Two species are considered as target species; cod and flounder. Herring, sprat and the by catch species (see the BITS manual) have been reported in the years 1991 to 1998. However, it has been optional to report these species since 1999 and the database is therefore not complete with regard to these species. Data are given haul-by-haul as mean catch per unit of effort (CPUE) per length class (1 cm interval for all species except herring and sprat, which are reported in ½ cm interval). In addition, mean CPUE and mean weight per length, age, maturity and sex are given haul-by-haul for sub-samples of the target species.