Detecting marine species at risk with eDNAPublished: May 22nd 2019
Environmental DNA (eDNA) is a promising new tool for environmentally monitoring living organisms in water and on land. It works by analyzing DNA found in expelled skin samples, feces, etc. collected from environmental samples (e.g. of seawater, soil and even air) to determine what species are present. eDNA is non-invasive and can be done at considerably lower sampling effort and cost and has been shown to be an effective monitoring tool in many environments.
But how effective is eDNA for monitoring marine species at risk in turbulent marine conditions like the Minas Passage in the Bay of Fundy where more than 160 billion tons of seawater flow through twice a day driven by the world’s highest tides? In partnership with Genome Atlantic, the Offshore Energy Research Association of Nova Scotia (OERA), the University of Guelph, and Dalhousie University, Stantec’s Dr. Marc Skinner is trying to answer this question.
The Minas Basin is home to several marine species at risk such as striped bass, Bay of Fundy salmon and Atlantic sturgeon that are important to First Nations and inshore fisherman. It’s also the site of planned tidal power development. Maintaining the health of marine species and monitoring the environmental effects of tidal development sites on these species will require a science-based approach and the best tools of the trade. Dr. Skinner, Stantec’s Marine Ecology Technical Leader for Canada, believes that eDNA could be a promising option in this regard.
“Traditional sonar and fisheries methods weren’t able to adequately capture the diversity and richness of species, including species at risk, in the Minas Basin, so we were asked by OERA if eDNA had a role to play in helping do that, in a more objective fashion.”
To find out, Dr. Skinner is carrying out a laboratory-based study conducted at Dalhousie University’s Aquatron facility in Halifax, which can simulate multiple marine conditions. The project, which is supported by a Genome Atlantic Genomics Opportunity Review Program grant, is using striped bass as the sample species. Dr. Skinner and his team hope to develop a ‘proof of concept’ for eDNA’s effectiveness and reliability as an environmental monitoring tool in high flow marine conditions – ultimately, providing reliable data for monitoring the environmental impact of developments such as tidal turbine projects on marine species.
The study has answered several critical questions. The first is whether the technology can detect the striped bass DNA at different levels of the water column – the answer being a resounding yes. (The Aquatron marine simulation tanks are as deep as a two-storey building is tall.) Secondly, Dr. Skinner wanted to determine how long the DNA signal is detectable after the fish leave an area. He discovered that DNA is readable for up to 24 to 48 hours, after which it starts to break down. Thirdly, he was able to demonstrate that eDNA can be used to measure relative abundance of certain species in an area, such as how many striped bass were present in an area over a two-week period.
Having tested the technology in both benign and turbulent simulations in the Aquatron, Dr. Skinner will soon take the equipment into the field, testing it in the Minas Basin. Given the results so far, he is hopeful that eDNA will prove to be a useful environmental monitoring tool in challenging marine conditions.
“EDNA can certainly be an effective tool for species detections and quantifications like we’re using in this project for species at risk,” he said. “But overall, the potential application of eDNA and genomics in the ocean space is virtually unlimited – for example, for biodiversity assessments, tracking pathogens and invasive species, ocean exploration for resource development, prospecting for oil and gas seeps, asset integrity, infrastructure development….the list goes on.”
Genome Atlantic will provide an update on this and other eDNA projects in the near future. Stay tuned for some exciting innovations in the ocean space!