AFSC Study Looks at Range of eDNA in Marine Fisheries Management

Alaska Fisheries Science Center.

New research by the Alaska Fisheries Science Center (AFSC) in Juneau examines the influence of distance and tides on distribution and concentration of environmental DNA from chum salmon in net pens in Southeast Alaska.

It’s another piece of the puzzle as researchers work to understand the overall impact of changing climate conditions on ocean fisheries.

This study, AFSC research geneticist Diana Baetscher said, addresses one of the critical knowledge gaps in applying eDNA to marine fisheries management.

“The idea here is we are able to use eDNA to understand where the fish are,” she said. “What we did with the chum hatchery net pen in Juneau was an experiment to determine where we no longer detect this eDNA. It is just a piece of information floating around in the water that we can sequence it and identify what fish sheds that.”

Study results announced March 13 by the National Oceanic and Atmospheric Administration (NOAA) offer background information that will help fisheries scientists better determine where these fish are in the ocean, Baetscher said.

“It is a new tool to understand fish distribution,” she added.

Temperature is one factor causing eDNA to degrade over time. The warmer the temperature, the faster the eDNA degrades, she explained. “The way the water is moving will determine the impact of how far away we can detect the fish from where it exists.”

Researchers engaged in this study determined that eDNA detections of marine fish are likely representative of present or recent proximity of those species, especially in environments with significant water movement, such as tidal swings or current.

The study found that it’s possible that the nearshore represents a more complex system for eDNA dispersal than deeper offshore waters, in which case, hydrodynamic models may be of greater benefit to studies of eDNA transport offshore.

Further studies that explicitly test offshore dispersal are expected to add valuable context to eDNA collections geared toward characterizing the distribution of fishery species.