Variation in within-river habitat use and migration patterns is an important yet poorly understood component of diadromous life history patterns. This project focuses on the catadromous barramundi (Lates calcarifer) in the Victoria River, Northern Territory, Australia. This river is nearly 800 km long and unregulated, allowing a unique opportunity to assess habitat use and spawning frequency in a minimally-impacted system. We have used a combination of elemental and isotope ratios to track movement between fresh and marine habitats as well as specific regions within the river to comprehensively characterize habitat requirements.

This work is in collaboration with Dr. Malcolm McCulloch (University of Western Australia) and Dr. Tim Dempster (University of Melbourne).

Work from this project has been published in PLoS One (DOI: 10.1371/journal.pone.0018351)

Population mixing in the marine environment is notoriously difficult to quantify, and otolith natural tags have allowed unprecedented insight into stock-specific distributions. Anadromous fish species are ideal candidates for these investigations because freshwater chemical signatures tend to be geographically distinct at finer spatial scales than those in the marine environment. This ongoing work draws upon a large database of ground-truthed natal signatures from 20 natal rivers across the native range of American shad (Alosa sapidissima). These signatures are now being used to identify origins of immature migrants captured in marine environments and compare those with previous mark-recapture results from adult migrants.

This work was done in collaboration with Dr. Simon Thorrold (Woods Hole Oceanographic Institution) and was funded by NSF. Publications from this project can be found on the Lab Publications page.