Trout diets in the NSW Snowy Lakes
A preliminary study of food webs and trophic pathways in Lake Jindabyne
There have been anecdotal reports of reduced Rainbow Trout numbers and sizes.
Food limitations could be a potential cause.
How we study food webs
That's why we study both fish guts and stable isotopes.
Looking at fish diets is a good start, but we also need to understand how energy moves through the ecosystem.
What are stable isotopes?
Learn more about stable isotopes.
Stable isotope analysis is based on 'you are what you eat'.
The method uses carbon and nitrogen to trace the flow of energy through a food web.
Click Here We focussed on the lake edges and inputs from rivers.
We worked with the University of Canberra to study the energy pathways supporting:
> Rainbow Trout
> Brown Trout
> Atlantic Salmon
Results
Something every angler knows - confirmed by science.
Lake edges were important feeding habitats for all salmonids
Results
However, stable isotopes revealed that Rainbow Trout also gain energy from open water areas in the lake.
Results
There was also a linkage between Rainbow Trout diets in the Snowy River and the lake.
Next steps...
Stable isotopes are deposited in fish tissues over months and years, so taking a broader view is important.
This preliminary study provides a great foundation for long-term studies to support the fishery.