Use of environmental DNA to detect Eastern Sand Darter ( Ammocrypta pellucida Putnam, 1863) in large Laurentian Great Lakes embayments

Abstract

A single-species environmental DNA (eDNA) method was developed to sample for a small, benthic rare species, Eastern Sand Darter (Ammocrypta pellucida Putnam, 1863) in two large Lake Ontario embayments. Summer water sampling allowed for: (a) surveys of habitats (Wellers Bay) where traditional fish sampling gear could not be used; and, (b) a comparison between eDNA and seining-based detection probabilities at known occupied habitats (West Lake). In 2018, replicate (n = 3) 1 L water samples were collected from 90 Wellers Bay sites and 71 West Lake sites. A site-occupancy model, a hierarchical logistic regression model, was fitted to determine site occupancy, sample occupancy (presence of Eastern Sand Darter DNA in a water sample) and probability of detection (p) based on replicate quantitative polymerase chain reaction (qPCR) results for each water sample. Eastern Sand Darter was detected at 10 West Lake sites, but not from Wellers Bay. Mean site occupancy was 0.31 (0.12–0.70; 95% CLs), mean sample occupancy was 0.28 (0.09–0.58; 95% CLs), and mean detection probability in a subsample (i.e., successful qPCR amplification) given it was present was 0.40 (0.25–0.55; 95% CLs). While the eDNA method successfully detected Eastern Sand Darter from known occupied areas in West Lake, it was not more effective for assessing local site occupancy than traditional sampling methods, such as the seine.