Skip to main content

Fish Detection by eDNA

Fish Detection by eDNA
Illustration - Ron Finger

Emerging Science—If you have heard of eDNA (environmental DNA), I am betting it was in conjunction with detecting Asian carps entering the Great Lakes. If you have not heard of eDNA, it is a procedure for detecting the presence of an organism from a water, soil, or air sample. DNA (deoxyribonucleic acid) is the genetic material present in all living organisms. Within the DNA strands are sequences of nucleic acid (genes or DNA fragments), some of which are unique to that species. The eDNA in the environment may come from scales, mucus, feces, gametes, or decomposition of the dead organism. Detection of a DNA fragment unique to a species is proof that the organism is somewhere in the system. Although technically complex, the process is largely automated allowing the rapid and economical assessment of many samples.

While good for surveillance, especially for unwanted invaders like Asian carp or zebra mussels, could eDNA be useful for assessing the abundance of fish populations? Collaborative studies by Arizona Game and Fish Department, U.S. Fish and Wildlife Service, U.S. Geological Survey, and University of Arizona fishery scientists attempted to answer whether eDNA measures were related to fish abundance, at what level of fish abundance were they detected by eDNA, and other important questions.

In 21,000-acre Roosevelt Lake, abundance of gizzard shad and largemouth bass estimated by gill net and electrofishing catch rates of gizzard shad and largemouth bass were little related to eDNA results.* eDNA was more effective at estimating shad than bass, possibly because the water samples for eDNA analysis were taken near the surface of open water where the shad live.

Studies in three streams in Arizona and New Mexico compared the detection of two rare bluehead sucker species by snorkel surveys and eDNA sampling.** The suckers were detected by snorkelers in all three streams but only in two streams by eDNA. The results suggest that there may be a threshold effect—a certain density of fish is needed to have a high likelihood of detecting the fish’s presence by eDNA.

eDNA will not make skilled fishery biologists tending gill nets and operating electrofishers obsolete, and it is hard to get fish population size structure and growth rate from a DNA sample. But eDNA will be a very valuable tool as aquatic resource managers become increasingly concerned about loss of biodiversity and accrual of unwanted invaders.

*Perez, C. R., and 8 co-authors. 2017. Comparison of American Fisheries Society (AFS) standard fish sampling techniques and environmental DNA for characterizing fish communities in a large reservoir. N. Am. J. Fish. Mgmt. 37:1010-1027.

**Ulibarri, R. M., and 5 co-authors. 2017. Comparing efficiency of American Fisheries Society standard snorkeling techniques to environmental DNA sampling techniques. N. Am. J. Fish. Mgmt. 37:644-651.

GET THE NEWSLETTER Join the List and Never Miss a Thing.

Recommended Articles

Recent Videos

Berkley's Manager of Fish Science and Bait Testing Mark Sexton and Project Engineer and Bait Designer Kyle Peterson talk about the finer points to Berkley's award-winning vibrating jig, the Slobberknocker.

The Birth of the Berkley Slobberknocker

Captain Ross Robertson explains how he uses Dipsy Divers to get deep to summertime walleyes. He covers the nuances anglers should understand with multi-directional Dipsy Divers, when using various baits such as spoons or crankbaits.

Using Dipsy Divers to Target Deep Walleyes

When retrieved lures start to veer to the left or right, there's an easy fix. Captain Ross Robertson show us how to tune our crankbaits with basic household tools to keep them retrieving the way we want.

How to Tune your Crankbaits

Captain Ross Robertson shows us how he prepares for cold-weather boat launching. As boat ramps potentially get slick and sketchy, certain gear comes in handy to stay safe, protect your investments, and keep you fishing longer.

Cold-Weather Boat Ramp Tips

Bailey Eigbrett demonstrates how the Humminbird Helix 10 CHIRP Mega SI+ GPS G4N CHO can help you find fish off shore and down deep, even if there is no pre-existing contour map for your lake.

Using Humminbird Helix 10 CHIRP Mega SI+ with a Kayak

Mike Carney of Kayak Fishing Fun takes you inside Quest Watersports with Paddle Manager Chris Kujawa to discuss the items to consider when deciding on a certain Hobie model of Kayak.

Top Considerations When Buying A Fishing Kayak

Thomas Allen of In-Fisherman gives us a lesson on cat fishing. Showing you where to find them, the equipment to use, and just how fun it can be to hook one.


A new partnership with SPRO means more availablity of KGB Chad Shad swimbaits. Learn more in this video from ICAST 2022 in Orlando.

KGB Chad Shad 180 Now in 5 Colors

New-for-2022 products from Lithium Battery Power can power everything needed for kayak fishing. With In-Fisherman's Thomas Allen at ICAST 2022 in Orlando.

Power Options for Kayak Anglers from Lithium Battery Power

In-Fisherman Magazine Covers Print and Tablet Versions

GET THE MAGAZINE Subscribe & Save

Digital Now Included!


Give a Gift   |   Subscriber Services


Buy Digital Single Issues

Magazine App Logo

Don't miss an issue.
Buy single digital issue for your phone or tablet.

Buy Single Digital Issue on the In-Fisherman App

Other Magazines

See All Other Magazines

Special Interest Magazines

See All Special Interest Magazines

GET THE NEWSLETTER Join the List and Never Miss a Thing.

Get the top In-Fisherman stories delivered right to your inbox.

Phone Icon

Get Digital Access.

All In-Fisherman subscribers now have digital access to their magazine content. This means you have the option to read your magazine on most popular phones and tablets.

To get started, click the link below to visit and learn how to access your digital magazine.

Get Digital Access

Not a Subscriber?
Subscribe Now

Enjoying What You're Reading?

Get a Full Year
of Guns & Ammo
& Digital Access.

Offer only for new subscribers.

Subscribe Now