Elemental Fingerprints of Sparus Aurata Otoliths – Insight Into the Diversity of Nursery Habitats

This study aims to determine if otolith chemistry can differentiate between coastal lagoons and shallow coves and if it can effectively re-assign Sparus aurata specimens to the nearest nurseries. Young-of-the-year (Y-O-Y) and young adults were collected at fifteen sites within three nurseries along the eastern Adriatic. LA-ICP-MS was used to quantify the concentrations of 12 chemical elements in the otolith region corresponding to the juvenile nursery stage. The multivariate element concentration differed significantly among nurseries. Based on CAP analyses, using a suite of five trace elements (Sr, Mg, Zn, Ba and Pb), 41% S. aurata specimens were correctly re-allocated to the nurseries and a higher rate of success (46%) was achieved for shallow cove than for coastal lagoons. A separate CAP analysis explained 94% of element variance, with 100% discrimination for Sr:Ca, Mg:Ca and Pb:Ca, enabling re-allocation to shallow cove nurseries. The lowest success of Ba as a discriminant reduced re-allocation to shallow coves. The results suggested that number of shallow coves with continuous, submarine, freshwater springs along the coast, making them similar to coastal lagoons, could significantly contribute to the S. aurata recruitment, expanding attention from the protection of individual nursery towards a wider part of the coast.