The adage “you are what you eat” rings true in the aquatic environment as the trophic position an organism occupies in a community is based on its diet and feeding behaviour. Traditionally, researchers used stomach content analyses to understand the trophic positions of animals. MEG researchers use these methods in conjunction with stable isotope signatures in the animals, which act as biological tracers of diet over time scales of months.

Our recent publications have included using stable isotopes to analyse gurnard, sawshark, cownose ray, marlin and great hammerhead ecologies and geographic ranges and routinely use at least three isotope types. We have also used stable isotope analysis on parasites residing on marlin to help decipher which water bodies these fish have moved through.