Morphological and meristic differences among spawning aggregations of north‐east Atlantic herring, Clupea harengus L.

Univariate and multivariate analyses were performed on seven anatomical characters of Atlantic herring, Clupea harengus , sampled from seven discrete spawning grounds to the west of the British Isles and from spawning sites in the Baltic and Thames Estuary. Analysis of mean similarities, Mahalanobis D 2 , percentage overlap and projections from prinicipal co‐ordinate analysis demonstrated that a high degree of anatomical similarity exists among the herring spawning communities to the west of the British Isles. Although local aggregations had distinct centres of abundance they appeared to have large overlapping distributions. However, the Celtic Sea sample was found to be distinctly different from adjacent and neighbouring stocks. The samples of coastal herring from the Thames Estuary and the Baltic Sea showed little overlap with other samples.