Detecting a spreading non-indigenous species using multiple methodologies

Abstract

Non-indigenous species (NIS) are often introduced to novel environments at very low population abundance. Detecting the presence of such an NIS can be very challenging, particularly as it spreads from the initial establishment site. This provides an opportunity to test detection limits using different approaches. This study tested the detection capability of 3 methods as zebra mussels (Dreissena polymorpha) spread from south to north through Lake Winnipeg, Manitoba, Canada. Zebra mussel veliger larvae were detected using cross-polarized light microscopy (CPLM), flow cytometry and microscopy (FlowCam), and conventional polymerase chain reaction (cPCR) analysis of environmental DNA (eDNA) on the same samples. Abundance generally declined from south to north in the lake but was lowest at Calder's Dock (central). Although abundances could be quite low (i.e., <1 veliger/m 3 , Calder's Dock) CPLM prevalence-the percentage of samples with at least one veliger-was high throughout the lake (99-100% of samples). Prevalence was lower for cPCR and FlowCam but was statistically associated with veliger abundance. Using standardized 3 mL subsamples (0.06-0.18 m 3 of lake water sampled), all 3 methods had a high probability of veliger detection if large numbers of samples were processed. FlowCam was the most expensive method to process these 3 mL subsamples, while cPCR was least expensive and fastest. eDNA combined with intensive sampling is the most practical method for wide-scale monitoring programs for early detection. However, all 3 methods are complementary and could be deployed sequentially, with rapid initial sample processing using PCR, confirmation and density estimation with FlowCam, and detailed veliger counts using CPLM.

Nuevos registros de los bivalvos invasores del género Corbicula del estado de Sergipe, nordeste de Brasil

“…Registros de ocorrência de espécies exóticas invasoras em novos ambientes iguais a esse são um importante contribuição para o conhecimento dos padrões de distribuição desses organismos tanto a nível global quanto localmente. A detecção precoce desses indivíduos, por sua vez, é fundamental para a aplicação de estratégias de manejo mais eficientes visando tanto o controle quanto a erradicação dessas espécies do ambiente (Brown et al, 2016;Johansson et al, 2020). Uma vez detectada a presença dessas espécies invasores na sub-bacia do Rio Jacarecica, novos estudos serão necessários para determinar a distribuição delas ao longo da sub-bacia bem como para avaliar os efeitos das interações entre as duas espécies invasoras e entre elas e as espécies nativas bem como avaliar os possíveis impactos gerados por elas no ambiente.…”

Catch me if you can: current status and topical issues on the use of eDNA-based targeted detection of rare and endangered animal species

“…This is not surprising since freshwater ecosystems are considered the most imperilled habitats in the world (Reid et al, 2019), and at least in temperate regions they have been subject of intensive monitoring due to legal requirements, as already above-mentioned. In these ecosystems, most studies have been conducted in rivers and small streams (Castañeda et al, 2020;Ma et al, 2016;Mizumoto et al, 2020;Piggott, 2017;Riaz et al, 2020;Rodgers et al, 2020), lentic ponds (Adams et al, 2019;Geerts et al, 2018;Harper et al, 2018b) and lakes (Johansson et al, 2020;Kamoroff and Goldberg, 2018), to a small extent in reservoirs and dams (Nakao et al, 2023;Sepulveda et al, 2022Sepulveda et al, , 2019, channels (Beauclerc et al, 2019;, caves and springs (DiStefano et al, 2020;Vörös et al, 2017) and aquacultures (Deutschmann et al, 2019;Ladell et al, 2019) (Table S2).…”

Improving Environmental DNA Sensitivity for Dreissenid Mussels by Targeting Tandem Repeat Regions of the Mitochondrial Genome

“…Targeted species-specific assays tend to be more sensitive than broad metabarcoding approaches [22]. Furthermore, cPCR has been found to be a fast and cheap method for the early detection of dreissenid veligers [24]; however, cPCR is typically less sensitive than qPCR [25] and is limited in its quantification output [22]. While qPCR provides the highest molecular sensitivity for eDNA analysis, it has failed to detect ZMs within Lake Superior from locations of low abundance [26].…”