Variability of stable isotope ratios of mangrove glassfish (Ambassis Jacksoniensis) from southeast Australia and the implications for ecosystem studies

Abstract

Scientists concerned with organic matter flow and food web structures in aquatic ecosystems are increasingly realizing the potential of stable isotope ratios as natural tracers. Stable isotopes offer an accurate and cost effective way to understanding critical pathways of energy and pollutant transfer. Further, many aquatic habitats have been degraded and isotope ratios offer insights into appropriate conservation and rehabilitation techniques to manage these valuable resources. So far, the literature shows little attention has been paid to spatial and temporal variations in isotope signatures of samples taken from saltmarsh and mangrove environments. This study reports on investigations into the differences in isotopic signatures within a single species, Ambassis jacksoniensis, surveyed from two locations at two different times. The results suggest significant variation in δ13C between different season and location for glassfish, but not for δ15N. The results also suggest that care is needed in interpreting previously published results. © 2007 Rosenstiel School of Marine and Atmospheric Science