Miss Maïlys Picard1,2, Dr Xavier Pochon1,3, Dr Anastasija Zaiko1,3, Dr David Kelly1, Dr Marcus Vandergoes4, Pr Ian Hawes2, Dr Susie Wood1
1Cawthron Institute, Nelson, New Zealand, 2University Of Waikato, Hamilton, New Zealand, 3University of Auckland, Auckland, New Zealand, 4GNS Science, Lower Hutt, New Zealand
The introduction of non-indigenous fish can have profound impacts on lake environments. Understanding the distribution of these species is essential to manage their impacts and limit their dispersal. Traditional methods for detecting fish can be time-consuming and inefficient, especially when biomass is low. This study used molecular methods targeting environmental DNA (eDNA) to estimate the occupancy of two non-native fish, the pelagic European Perch (Perca fluviatilis) and the benthic rudd (Scardinius euryphtothalmus). Environmental DNA was extracted from water and surface sediment samples from the littoral and pelagic zones of three lowland lakes from New Zealand’s North Island (Tomarata, Waitawa, and Pounui). Detectability of each species was compared between water and sediment samples using droplet digital PCR (ddPCR), as well between ddPCR and metabarcoding methodologies for one lake only. The use of a new bulk extraction technique for the sediment samples improved detection probabilities, which were overall higher than for water samples. Quantification using ddPCR was more sensitive than metabarcoding. This study demonstrates the applicability of eDNA techniques for detecting the presence of both pelagic and demersal fish species, as well as estimating its occupancy over larger geographic scales. These results suggest including eDNA into non-native fish surveillance programmes will help support decision-making and effective management.
Biography:
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