Otolith shape and meristic analysis of herring (Clupea harengus) in the North-East Atlantic

Two sets of phenotypic markers, otolith shape and meristics, were used to i nvestigate the morphological structure of herring populations of the North- East Atlantic and to test the application of the truss method on otolith sh ape to discriminate between the populations. Otolith and meristic analyses displayed similar patterns of differentiation between the herring populatio ns, revealing a discreteness of the Icelandic summer spawners, Trondheimsfj ord herring, Baltic herring and the British Isles groups. The pattern of ph enotypic discreteness detected with meristics and analysis of otolith shape suggests a direct relationship between the extent of phenotypic divergence and the geographic separation of the populations, indicating that geograph ic separation limits migration between the populations.