PCA results made with otolith near-core signatures . First two PCA axes of trace element concentration signatures (²⁴Mg,³¹P, ⁸⁶Sr and ¹³⁸Ba) for all narrow-barred Spanish mackerel samples (left) and only for samples 70-90 cm (right). Sampling events are: Egypt in summer (Egy-S),North Djibouti during summer (Dji-N-S), North Djibouti in winter (Dji-N-W), South Djibouti in winter (Dji-S-W), Somalia in summer (Som-S), Mozambique inwinter (Moz-W) and South Africa inwinter (Sa-W). Fish sampled in winter are in blue and fish caught in summer in red. The black arrows represent the contribution of each trace element to the first two PCA axes.