Clusters obtained using agglomerative Ward's hierarchal clustering applied to the core of the otolith of all fish samples. All sampling event are represented on top row (a, b) while bottom row (c, d) includes only sampling events in Egypt, Djibouti (North and South) and Somalia and excludes samples caught in Mozambique and South Africa. Barplots on the right (b, d) indicate the number of individuals from each sampling event that were assigned to the different clusters (with (b) corresponding to the clusters in (q), and (d) corresponding to the clusters in (c)). The x-axes on the barplots represent the number of individuals for each sampling event colored by their assigned cluster.