On the "Racial" Structure of North Sea Autumn-Spawning Herring

Evidence on meristic and morphometric characters tends to support a division of North Sea autumn-spawning herring into three, mainly self-contained stocks - the Buchan, Dogger and Downs herring -, which show differences in spawning areas an spawning periods. SCHUMACHER, using gill-raker counts only, separates the North Sea autumn-spawning herring into two groups, a north group and a south group. In his concept the Dogger stock is a mixture of young north (Buchan) fish and older south (Downs) fish. An analysis of an extensive material on vertebral counts, keeled scales, /1, otolith-types and egg-size ofDogger spawners show all these characters not to be changing with age within a year-class of Dogger fish, when at the same time these characters did show significant differences etween Downs spawners and young Dogger spawners. It also proved impossible to trace the effect of relatively poor or strong Downs year-classes in the abundance of older Dogger herring. On these grounds SCHUMACHER'S hypothesis concerning the mixed character of the stock of Doggerspawnersis rejected andsuggestions are made to solve the apparent conflict between SCHUMACHER'S data and the material presented in this paper.