Mr Alexander Vaishampayan1
1University Of Melbourne, Melbourne, Australia
This project aims to develop an environmental DNA (eDNA) tool to estimate the biomass of native and non-native fish species in Victoria’s streams. The specific objectives of this experiment will be to determine if there is a measurable difference in the eDNA concentration relative to the biomass of fish present, to assess whether that difference is large and consistent enough to form the basis of population models, and to examine how stream flow rates may alter the distance which fish DNA is detectable.
This project consisted of two parts, the collection of water samples for eDNA analysis and a standard electrofishing survey for measurement of fish biomass. A site was a 250m stretch of steam sectioned into five 50m zones with stop nets. At the downstream stop net of each zone an eDNA sample, as well as stream depth and water velocity measurements, were taken midstream and at both banks. Starting from the most downstream zone, an electrofishing survey made three electrofishing passes. Individuals of the three target species (brown trout, rainbow trout and river blackfish) were counted, measured, and weighed to determine the biomass of each species in each zone. The process was repeated moving upstream in the other 4 zones. For eDNA measurement, a single-species primer will be used to find the eDNA concentration.
Field work was undertaken at three sites around Lake Eildon, Victoria. We collected 17 brown trout, 48 rainbow trout and 227 blackfish. eDNA analysis was planned for October, 2022.
Biography:
Alex is a PhD candidate at the University of Melbourne working on the Victorian recreational trout fishery. In addition to his project on eDNA, he also works on the social aspects of fisheries management. His background working with Native Americans in the USA has motivated him to focus on how to balance environmental conservation with the cultural and economic needs of the people involved in the fishery.