Date of Award

2017

Degree Type

Thesis

Degree Name

Master of Biological Science

School

School of Science

First Advisor

Dr Annette Koenders

Second Advisor

Dr Quinton Burnham

Third Advisor

Dr Michael Snow

Field of Research Code

0 5 0 2 0 2

Abstract

The challenges associated with environmental monitoring such as the impact on the environment and the financial costs are problems we face when trying to conserve freshwater systems around the world. The need for precise and accurate results that are cost effective is important so that we can achieve our conservation goals.

The overall aim of this study was to explore Next-Generation - metabarcoding for the detection of feral and native freshwater fish species based on the DNA shed by individual organisms into the water column. Cytochrome c oxidase I (COI) primers were developed for this study using DNA from six freshwater species expected to be found in the waterbody. These primers, along with 16S rRNA (16S) primers, were assessed to ensure that the molecular method was robust and suitable for use in the field. Along with the cost effectiveness of the molecular method when compared to the more traditional surveying method of Fyke net surveying.

This study comprised development of field and lab protocols for the detection of freshwater fish species in a lentic system. Both the COI and 16S primer sets showed results that were comparable to previous Fyke net surveys, though both primer sets detected species that the other did not. Further qPCR analysis showed that there were differences in detection for both primers for each of the species. The molecular surveying of the waterbody has been proven sensitive enough to detect Maccullochella peelii. This species has a very low abundance in the waterbody (believed to be n=1) so these results suggest that this method can be used to target low abundance species.

The outcome of this study highlighted the need for multi-location sampling within a waterbody as increasing the number of locations sampled, led to an increase in the number of species detected. Along with the multi-location sampling, it was also important to sample throughout the year to account for seasonal variability. The eDNA study emphasized the importance of having knowledge of both the ecology and the biology of the species targeted so that a robust monitoring method can be implemented.

As well as comparing the apparent accuracy of Fyke netting and the eDNA approach in the study waterbody, a cost benefit analysis comparing the relative costs of multiplex DNA surveying, single species molecular surveying, and Fyke net surveying was undertaken. Molecular environmental surveying was found to be a cost effective method for monitoring, as the analysis suggested single species monitoring would break even after only 95 waterbodies were surveyed, and multiplex surveying would break even after 145 waterbodies, under the proposed scenario. The cost benefit analysis explored the costs associated with all three methods, including lab set up costs, along with the number of waterbodies that could be surveyed on both a weekly and yearly basis.

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