Tuesday, April 24, 2018

Mussel Detection Technology - Aquatic Invasive Species

     "I imagine you are all really into aquatic invasive species news," Heidi joked. If we were, we would know about the new techniques for detecting mussels. As the only remaining US watershed without them, we are concerned with making sure we stay that way. To do so, we must be vigilant and quick to detect them if they arrive.

     Mussel larvae, also know as veligers, were first detected in the Tiber Reservoir and Canyon Ferry in the fall of 2016. This marked the first time mussels had been found in Montana. Thankfully, these locations are not connected to the Columbia Watershed, so all the lakes and rivers on the Western side of the continental divide are safe, for now.

Related image
Zebra mussel veliger
Source: NOAA Great Lakes Environmental Resource Laboratory

     Detection efforts typically involve examining water samples using microscopy, Heidi said. Dogs are also used to inspect boats, shorelines, and docks, as they're trained to sniff them out. Imagine those police dogs that are used to find bomb residue and drugs, but instead of stationing them at an airport or police station, these dogs get to explore the shores of Montana lakes, seeking out tiny little shelled creatures. The students must've had a similar mental picture, because a few of them laughed. Dogs were deployed in November 2016 and confirmed the presence of mussels in the Tiber Reservoir and Canyon Ferry. US Fish & Wildlife Services has also utilized scuba divers to search for signs of mussels. Using divers brings up silly images of people wandering around underwater looking for something dark in the dark, but it's a lot easier to send people down in scuba gear with flashlights to check underwater features and pipes for mussel colonies than it is to send dogs!

Image result for mussel detection dogs
Mussel inspection dog
Source: Working Dogs for Conservation

     A more recent development in detection technology analyzes environmental DNA, or eDNA. No, this doesn't mean the environment has its own DNA. eDNA is the remnants of DNA left behind by organisms as they shed cells, excrete waste, and rub against other things, like water or rocks. Some form of eDNA detection has been used for several years, but researchers at the Flathead Lake Biological Station have been working on ways to make it work with smaller samples and smaller budgets. This method can help researchers detect mussel presence at all stages of the mussel life cycle. Heidi summarized that in 2016, dogs, divers, and microscopy all found evidence of mussels, but later in 2017, only eDNA did. The question with eDNA, Heidi said, is whether eDNA indicates current presence of mussels if dogs or divers don't find any veligers.

     Since the technology is so new, there aren't standard procedures for how to collect and test eDNA, or how to interpret a positive test result. Perhaps eDNA lingers around after all living veligers and adult mussels are eradicated, or perhaps the DNA breaks down quickly and finding it means mussels are indeed lurking in our waters. As further research is conducted, this method may become more accurate at detecting low populations of mussels, perfect for taking early and quick action.

     Discussing the lengths to which we go to detect mussels helps drive home how important it is to keep them out. It also gives students an idea of how researchers and agencies are approaching the problem, and the creativity of new technology. When I was a young student, "research" sounded like sifting through stacks of papers or doing experiments in stuffy laboratories, but the development of eDNA analysis demonstrates that research attacks real world problems and ultimately tests solutions in the field, too. I think it's important to expose students to the developments in technology and problem solving so they can envision themselves doing the same thing in the future.

-Cassie Sevigny
AmeriCorps Team Member
Media Coordinator

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