Environmental Signature in the Otolith Elemental Fingerprint of Several Important Commercial Fishes in Yangtze River Estuary, China

There are approximately 300 species of fish in the Yangtze River, the largest river in China; one-third of these mostly migratory fishes inhabit the Yangtze River Estuary and many of them are economically important species, e.g. Coilia mystus, Coilia nasus, Mugil cephalus, Cynoglossus gracilis, Collichthys lucidus. Human influence, including overfishing, water pollution, hydropower and dam construction, have sharply reduced the natural population of these fishes, which would result in a loss of biological diversity. In order to effectively manage and conserve these important fishery species, it is critical to achieve an understanding of their present situation, both as individuals and as groups, based on their ontogenetic patterns of habitat use and migration by means of the valuable approach of otolith elemental fingerprint. Those results of Sr and Ca analyzed by wavelength-dispersive X-ray spectrometry on an electron microprobe analysis (EPMA) technologies (‘life-history transect’ and X-ray intensity map analysis) suggested that there will be diverse for the migratory pattern and group composition of these fish. This means that the species can use freshwater, brackish or marine habitats to different degrees and appear to show behavioral plasticity in their use of estuarine and marine habitats.