Estuarine dependency in Collichthys lucidus of the Yangtze River Estuary as revealed by the environmental signature of otolith strontium and calcium

This paper represents the first effort to study the environmental Sr and Ca signatures in otolith of spinyhead croaker Collichthys lucidus, an economically important sciaenid fish in China, by means of Electron Probe Microanalysis. Results from life-history transect analyses and X-ray intensity maps suggested that all croakers in this study collected from the Yangtze River Estuary were estuarine-resident individuals, in contrast to previous reports that C. lucidus is a marine fish. However, the high Sr core suggested that the stimulation of relatively high salinity water seemed to be required for spawning, embryogenesis and early larval growth of C. lucidus.