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  • Writer's pictureBen Martens

PODCAST: The opportunity of eDNA for Maine's fisheries

*Note: the Soundcloud plugin wasn't working so please hit the button to listen to Maine Coast Dock Talk

Environmental DNA, or eDNA, is a method of detecting and monitoring species by collecting their DNA from environmental samples like water, soil, or air. This technique does not require the physical capture of organisms, making it a non-in

vasive and hopefully efficient method for biodiversity studies.

In the context of fisheries in New England, eDNA can be particularly significant for several reasons:

  1. Species Identification and Biodiversity Assessment: eDNA allows for the identification of various species present in a particular aquatic environment without needing to capture them.

  2. Monitoring of Invasive Species: eDNA can detect these invasive species early, aiding in prompt management actions.

  3. Stock Assessment: eDNA may be able to be used to estimate fish populations and distribution, providing critical data for sustainable fisheries management.

In 2022, Maine Coast Fishermen’s Association partnered with a class from the University of Maine to build a project to test the ability of eDNA to see what species are in the waters off of Monhegan Island. The area selected for sampling is set to have a full-sized wind turbine built and anchored to the seafloor and there are questions from the fishing industry as to the impacts this may have on local wildlife.

The project was a small-scale attempt to test out eDNA for stock assessments in areas with offshore wind turbines. Turbines could potentially obstruct future trawl surveys which are a key

part of the stock assessment process. eDNA may be a part of a possible solution.

The Monhegan study found evidence of cod, haddock, and Atlantic salmon in surface water samples. In midwater samples, eDNA from cod, haddock, Atlantic salmon, bluefin tuna, flounders, and flat fish was gathered. On the sea bottom, researchers discovered samples of cod, haddock, Atlantic salmon, founders, and flatfish. The study also detected mackerel scad, cusk, big-eyed scad, Atlantic bonito, American plaice, and swordfish.

EDNA is not a fully developed method, and this particular method is only a snapshot in time. In the water, it is diluted and shifted by currents and is usually only reliable for very short periods of time; the data can change by the hour and an effective study requires many more samples than what was tested off of Monhegan.

The study is an exciting snapshot into the future of fishery management. As research continues and eDNA becomes more reliable, it presents an inexpensive, non-invasive approach to accurately determining what fish are where. Fisheries everywhere are data-hungry and searching for ways to best track the fish they hope to steward. When it comes to offshore wind development, the customary stock assessment methods may not be possible. With eDNA as a tool, the gaps in understanding may close.



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