Federal fisheries officials say a long-term environmental DNA research project will offer better understanding of nearshore habitats for fish and crab in Alaska and help support sustainable fisheries management.
Resource managers at NOAA Fisheries Alaska Regional Office, the North Pacific Fishery Management Council and the U.S. Army Corps of Engineers are all interested in this project for its potential to identify coastal habitat critical to fish and crab and to offer information vital for sustainable coastal development and resource management decisions.
The project initially was a 2020 pilot study that identified over 40 species at nine sites around Juneau. Plans now are to conduct eDNA sampling in many other areas, including Prince William Sound, Kodiak, Baranof Island, and offshore habits in the Gulf of Alaska, Aleutian Islands and the Bering, Chukchi and Beaufort seas.
“We are excited about the possibility of using eDNA as a cost-effective way to learn which fish and crab species are present in specific locations throughout Alaska,” said Gretchen Harrington of the Habitat Conservation Division of the NOAA Fisheries Alaska Region.
“With this information, we can better identify, and promote the protection of, essential fish habitat and managed species.”
The long-term goal is to integrate eDNA research into Alaska Fisheries Science Center surveys to collect data for use in improved stock assessments and to help fisheries scientists better understand ecosystem processes. “We are also exploring using eDNA to understand fish and crab habitat use and distribution in the nearshore and to detect marine invasive species, such as European green crab,” said Harrington and Wes Larson, manager of the genetics program at the Auk Bay Laboratory.
“As budgets shrink,” they said, “We are continuing to find innovative ways to do more with less. We are particularly excited about pairing eDNA with un-crewed instrumentation such as remote autosamplers.”
The project allows researchers to use eDNA to get site-specific species presence/absence data for Essential Fish Habitat consultations with the Army Corps of Engineers and other federal agencies. Results may also be used to augment existing predictive habitat models used to map EFH by providing known presence/absence locations in rarely sampled regions, they said.
Using eDNA metabarcoding techniques may also help with development of predictive models for a suite of species and their habitat associations with coral, sponges and other benthic, or ocean-bottom, organisms, researchers said. This is critical to protect vulnerable species and determine the least sensitive areas for human activities to occur.
Water temperatures, water flow and clarity of the water all figure in how much can be learned from water sampling. Strong currents and tides can move eDNA around, but much of the water sampling in Alaska is done in cold and relatively dark environments, and eDNA persists longest in cold, dark environments with little water flow, Harrington and Larson said.
Harrington and Larson also sample many areas with low clarity, such as near glacial outflows.
“In summary all of these variables affect how we take samples and analyze data, but Alaska is a great place to study eDNA compared to, for example, the tropics, because of the cold and relatively dark conditions,” they said.