Heidi Pethybridge is a marine ecologist and bioenergetics modeller at CSIRO Oceans and Atmosphere, Hobart and was the recipient of the ASFB ECR International Travel Award in 2015. Her research focuses on the biology of marine fish populations through the use of modern ecological technology, mostly biochemical tracers and bioenergetics models. Heidi is currently co-leading a task team in the GLOBEC/CLIOTOP (Climate Impacts on Oceanic Top Predators) program that is undertaking global diet and stable isotope analyses of three tuna species. She is an editor for the General Ecology and Behavioural Ecology sections in the 2nd edition Encyclopaedia of Ecology due for completion early 2018. Recently Heidi reviewed the most common biochemical tracers used to empirically assess marine ecosystem structure, function and services. This work focused on recent examples to show how parameters, datasets and indices derived from biochemical tracers can be used to validate the underlying assumptions and reduce uncertainty related to trophic interactions described in ecosystem-based models. With the support of ASFB, this review was presented at the 2016 International Society of Ecosystem Modelling Global Conference in Baltimore.