Results of the workshop on comparative age reading on sprat from ICES Div. IIIa

The paper presents results from comparative age reading on sprat otoliths from various areas within Div. IlIa. Readers from fishery laboratories in Denmark, Norway and Sweden participated in the workshop. The reproducibility of the readings between the laboratories was tested by coefficient of variation and index of precision. The results are presented by length groups and the ageing in each of the subareas Skagerrak and Kattegat. Low consistency in the ICES IBTS 1- and 2-group sprat, as demonstrated by the ICES Herring Assessment Working Group, may be explained by great variation in age determination