A new DNA method that could revolutionise the way fish are monitored in lakes has been shown to detect 14 of 16 key fish species known to be present in Lake Windermere, compared to just four species found by conventional surveys.
Fish are sensitive indicators of water quality and their assessment is an important part of water management. In England, Wales and Scotland regular lake fish monitoring is not feasible with existing tools and resources. Netting can capture all the fish in an area, but it is costly and can injure or kill fish.
The research project tested a new approach to assess both the type and numbers of fish present in three large lakes in Cumbria (Windermere, Bassenthwaite and Derwentwater)
The approach uses environmental DNA (eDNA) - the DNA that fish leave behind in the water from their skin, urine or faeces. The eDNA can be used to provide information on fish living in the lake. New technology allows all the DNA in a water sample to be sequenced and identified. According to the Environment Agency, the multi species identification method is rapid and sensitive and has real potential to change the way it carries out ecological assessments.
The work is part of a wider programme of research by UK agencies to develop DNA based methods for environmental monitoring and decision making.
Using eDNA is relatively new, and so far much of the research has focused on developing methods to assess the presence or absence of single species.
The next step will be to demonstrate that the findings can be repeated at different times of the year and that the method has wider applicability to a greater range of water bodies, such as those with varied chemical and physical properties.
The next step will be lead by the Scottish Environment Protection Agency (SEPA) and will include the assessment of Scottish lochs which are more nutrient poor and where fish (and eDNA) are likely to be found in much lower numbers as well as repeated assessment of Lake Windermere.
Click here to download the full report eDNA-based metabarcoding as a monitoring tool for fish in large lakes