Baltic Sea

Fish taxonomy-related counts

The international coordinated trawl surveys are directed to the demersal species i.e. cod and flounder and other flatfishes in the Baltic Sea, however in the recent two years other species are also intensively investigated to support ecosystem analyses. National parts of the international coordinated fish surveys should be carried out in the first quarter between 15 February and 31 March (spring survey) and in the fourth quarter between 1 and 30 November (autumn survey). The total distribution area of cod should be covered by the BITS trawl survey. It was agreed to make fish control-hauls during the trawl surveys because the stock size of the eastern Baltic cod is relatively low and is currently concentrated in northern areas of the Baltic Sea is possible dependent on the development of the eastern Baltic cod stock size and its spatial distribution pattern. The international trawl surveys are carried out in form of a stratified random survey. The ICES Subdivisions and depth layers within an ICES Subdivision are used as strata. Only depth layers from 10 to 120 m depending on the ICES Subdivision are covered by the surveys.

Anon (2002) ICES CM 2002/G:05., ICES

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