A validated targeted assay for environmental DNA detections of the Atlantic wolffish (Anarhichas lupus)

Abstract

AbstractThe Atlantic wolffish (Anarhichas lupus) was assessed as a species of Special Concern by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) under the Canadian Species-At-Risk Act (SARA) in 2001, and by the National Marine Fisheries Service in USA in 2004. Monitoring of marine Species-At-Risk would rely ideally on non-destructive methods. However, most monitoring of marine fish at-risk rely on trawl surveys that are potentially destructive of the environment. Inferring a species presence using environmental DNA (eDNA) detections offers an attractive alternative for Species-At-Risk monitoring, because it is non-destructive, specific, and sensitive. We developed and optimized a real-time quantitative PCR probe-based (qPCR) detection protocol that targets the eDNA of Atlantic wolffish, A. lupus. The qPCR protocol was validated in silico, in vitro, and in situ. Species-specificity was assessed in vitro by testing against the two other species of Anarhichas present in the northwest Atlantic. We did not observe DNA amplification for either of these two species. The assay was highly sensitive, with a limit of detection (95% confidence level) of 1.5 DNA copies per qPCR reaction. In situ tests showed that A. lupus eDNA is detected from expected depth strata in areas of known wolffish abundance. This study provides a proof-of-concept experiment that offers a robust, targeted, and non destructive protocol for detection eDNA of the Atlantic wolffish.