An environmental DNA‐based method for monitoring spawning activity: a case study, using the endangered Macquarie perch (Macquaria australasica)

Abstract

Summary1. Determining the timing and location of reproductive events is critical for efficient management of species. However, methods currently used for aquatic species are costly, time intensive, biased and often require destructive or injurious sampling. Hence, developing a non-invasive sampling method to accurately determine the timing and location of reproduction for aquatic species would be extremely valuable. 2. We conducted an experimental and field study to determine the influence of spawning, and the mass release of spermatozoa in particular, on environmental DNA (eDNA) concentrations. Using a quantitative PCR approach we monitored changes in nuclear and mitochondrial eDNA concentrations over time. 3. The data from the experimental study and the field survey supported our hypothesis that spawning events are characterized by higher concentrations of nuclear relative to mitochondrial eDNA. Outside of the reproductive period, we find that nuclear and mitochondrial DNA fragments are equally abundant in environmental water samples. 4. We have shown that changes in the relative abundance of nuclear and mitochondrial eDNA can be used to monitor spawning activity of the endangered Macquarie perch. Our method is likely to be transferrable to other aquatic species and can be particularly useful to increase our understanding of the spawning biology of cryptic, rare or threatened species as well as design and evaluate environmental management actions and determine species establishment.

Environmental DNA Sampling of Small‐Bodied Minnows: Performance Relative to Location, Species, and Traditional Sampling

“…; Bylemans et al. ). Furthermore, others have shown that persistence rates differ among streams of various sizes and characteristics (Wilcox et al.…”

Identifying spawning sites and other critical habitat in lotic systems using eDNA “snapshots”: A case study using the sea lamprey Petromyzon marinus L.

“…A range of sampling approaches has previously been employed which have varied in sample size from, for example, c. 1,000 × 2 L samples from a canal and waterway system (Jerde, Mahon, Chadderton, & Lodge, 2011), to 5 × 15 ml samples from a sea pen (volume of 4 million liters) within a harbor (Foote et al, 2012). Similarly, it has been confirmed that spawning events are characterized by a higher relative abundance of eDNA (Bylemans et al, 2017) making the spawning season an ideal time to utilize eDNA for biomonitoring within lotic systems. Quantifying eDNA to estimate the biomass of a target species in running water is invariably complicated and requires the consideration of many variables including eDNA shedding and degradation rate at time of sampling; water temperature; pH; salinity; flow rate; water volume; hydro-morphology; and the dendritic organization of the habitat (Rees et al, 2014;Roussel, Paillisson, Tréguier, & Petit, 2015;Thomsen et al, 2012).…”

Development and application of environmental DNA surveillance for the threatened crucian carp (Carassius carassius)

“…A quantitative polymerase chain reaction (qPCR) assay targeting crucian carp was also published in the context of early warning invasion monitoring for fish species that may arrive in Canada (Roy, Belliveau, Mandrak, & Gagné, ), but was only tested on tissue‐derived DNA. Of equal importance to invasion monitoring, eDNA analysis has enhanced surveys for threatened and endangered freshwater fish (Bylemans et al., ; Piggott, ; Schmelzle & Kinziger, ; Sigsgaard et al., ).…”