Effect of temperature and salinity on otolith element incorporation in juvenile gray snapper Lutjanus griseus

Abstract

Otolith chemistry provides one approach for identifying the relative contribution of juveniles from different nursery habitats to adult populations. The goal of this study was to validate otolith element incorporation by quantifying the relation between otolith and water element concen- trations (Sr/Ca, Mg/Ca, Mn/Ca, and Ba/Ca) as a function of differences in water temperature and salinity using juvenile gray snapper Lutjanus griseus, a reef fish that inhabits estuarine and near- shore habitats as juveniles. We investigated the effects of 20 different temperature (18, 23, 28, 33°C) and salinity (5, 15, 25, 35, 45) combinations on otolith element incorporation (partition coefficient D) in L. griseus. Temperature and salinity had significant effects on DSr but no significant effect on DMg or DMn; however, salinity had a significant effect on DBa. The broad range of temperatures and salin- ities used in the present study encompasses those occupied by juveniles in the wild and therefore provides a realistic test for using otolith chemistry to infer environmental history of individual gray snapper. Element incorporation and the effects of temperature and salinity on element incorporation differ among fish species, limiting development of generalized models aimed at predicting water chemistry from otolith chemistry. Thus, the data presented here underscore the necessity of valida- tion experiments to translate species-specific elemental signatures in otoliths.