Study Group on Herring Assessment Units in the Baltic Sea (SGHAUB)

This report presents three assessments for herring stock components in the Central Baltic (Subdivisions 25–29, 32 Gulf of Riga herring excluded) which were recommended and justified for separable assessment by the Study Group in the previous Reports (ICES 2001a, 2002a): 1) Herring in Subdivisions 28, 29 and 32 (excluding Gulf of Riga herring). The assessments of this herring stock were performed at the Baltic Fisheries Assessment Working Group in 2001 and 2002 (ICES 2001, 2002). The present assessment includes considerable changes of effort and CPUE data.2) Southern coast herring in Subdivisions 25–26. It is a fast-growing herring stock which is considered to spawn mainly along the southern coast of the Baltic Sea in Subdivisions 25–26 and which does not perform extensive feeding migrations outside the southern Baltic. Firstly it was distinguished by Kompowski (1969). It is distinguished in the catches by Polish and Russian scientists on the basis of otolith structure. The previous assessment of this stock was performed in 1991.3) Swedish coast herring in Subdivisions 25–27 spawns along the eastern coast of Sweden (Subdivisions 25 and 27) and performs extensive feeding migrations to the southern Baltic where it mixes in Subdivisions 25–26 with the southern coast herring stock. It is distinguished in the herring catches in Subdivisions 25–26 by the Polish and Russian scientists, but the population composition of the catches of other countries in this region is not known. It was assumed that in Subdivision 27 only Swedish coast herring is met. This herring stock component has never been assessed previously.