Otolith microchemistry in Sicydium punctatum: indices of environmental condition changes after recruitment

The amphidromous life cycle and morphological characteristics of Sicydiinae species allow them to colonise tropical freshwater habitats from the river mouth to the upper reaches of the river basin. Otolith microchemistry of 62 Sicydium punctatum from the Perou River, Guadeloupe (French West Indies) was investigated with a femtosecond laser ablation-inductively coupled plasma mass spectrometer (fs-LA-ICP-MS) in order to reconstruct individual life history and follow the possible movements of Sicydium punctatum after the recruitment. Sr: Ca fingerprint confirmed the amphidromous cycle of this species. Variations of Ba: Ca in some individuals indicated changes in environmental conditions after the recruitment in the river. Even if results did not allow concluding to the specific origin of these variations, the hydrological regime and the biofilm composition may have a non negligible influence on the Ba availability. Results supported the use of multi-elemental signatures in otoliths and highlight the need for a large geographical and temporal sampling of Ba and Sr in freshwater systems for a better understanding of amphidromous fish species.