eDNA is more than just a carp-finding tool

Scientists can use eDNA samples to answer many important fish management questions. (NOAA Fisheries photo)

If you’ve read anything about the efforts to monitor the spread of Asian carp through the upper Midwest, no doubt you’ve heard of eDNA. The “E” stands for environmental and the DNA is the kind of genetic code that can be gathered from the environment, not just sampled from a particular creature.

DNA is present in every cell from every plant and animal, but it’s also present in much of what living organisms leave behind in the form of dead skin cells, loose hairs or in waste. In the case of Asian carp, it’s the left-behind DNA strained out of waters being tested that researchers are trying to find. Finding it is a sort of “early warning.” If it’s present, further testing and sampling is warranted.

Of course, it’s not only Asian carp that can produce eDNA. So can you, me, bluegills, walleyes and every other creature on the planet. Scoop up a measure of water from any lake or stream, strain out the eDNA and DNA from each species of fish, frog and fly that has been in the lake’s water can be isolated.

Cool stuff, from a science point of view. But is it useful?

Some researchers from the University of Wisconsin are giving it a big thumbs up.

They say they can easily gather the eDNA; it’s as simple as scooping up a measure of water from the lake, taking it back to the lab and processing it. I’m not sure how the water is processed, but the report said the process can be done in one day.

The results from the sample can reveal exactly what sorts of eDNA were found and what species of fish are in the lake is revealed. That’s good information to know, but from a biological point of view, in most lakes, almost all the species found in the lake have already been cataloged.

Fisheries managers already have that information, but what they need to know more precisely is how many of each species are present. The Wisconsin researchers say they can further analyze the results and answer questions like: Are there very few bass but lots of crappies in the water? Does there appear to be enough forage fish to support the number of predator fish?

When a fish biologist has that information, he or she is well on the way to being able to determine many things, such as how many fish can be harvested sustainably from the lake. Are there management projects that  can be instituted to enhance the population? Would stocking fry or fingerlings be wonderful or wasteful?

The science of fisheries management has been around for well over a century. The science of eDNA may well be the biggest breakthrough in all that time – and will only become more important in the future.

Categories: Asian Carp, Blog Content, Michigan – Mike Schoonveld

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