The fast timeline from when the Idaho State Department of Agriculture discovered invasive quagga mussel larvae within the Snake River in September to when it deployed a chemical remedy two weeks later was unprecedented on the planet of invasive mussel management. Yet the unparalleled effort additionally brings a number of uncertainties about what occurs subsequent.
In two rounds of post-treatment surveys, company employees didn’t discover any mussels within the six-mile river stretch in Twin Falls. However, the state will not know if the remedy was efficient till subsequent spring. During the chilly winter months, mussel replica decreases, making it more durable to detect them after they’re not releasing hundreds of thousands of larvae.
It’s additionally unclear how lengthy it’s going to take for the river ecosystem to recuperate after tens of hundreds of gallons of a copper-based chemical had been poured in to kill the mussels. As anticipated, the remedy additionally killed most fish within the space. Idaho Fish and Game recovered over 3,000 useless fish from this stretch, weighing six to seven tons.
Most of the useless fish had been suckers, pikeminnow and perch. Fewer largemouth bass and sunfish died, Fish and Game mentioned. It’s attainable these fish swam out of the remedy space to keep away from the copper. Some species may return naturally, however sturgeon will should be reintroduced via hatcheries. Fish and Game estimated that every one roughly 50 sturgeon on this a part of the river died from the remedy.
During a Fish and Game Commission assembly, Eric Stark, the fishery program coordinator, acknowledged the company would probably delay reintroducing sturgeon till it is clear the river will not want additional remedy.
To higher perceive how the river may recuperate, some scientists are finding out the underside of the meals chain: aquatic bugs.
“We acquire them and protect them in ethanol, after which we ship them to knowledgeable taxonomist to take a look at them below scopes,” mentioned Christopher Mebane, the Deputy Center Director of the USGS Idaho Water Science Center in Boise.
The USGS will depend the species and variety of bugs within the river and examine that to the pre-treatment numbers. Mebane highlighted the dearth of precedent to foretell the river’s restoration.
“I’d say after they’ve completed related issues, however nobody’s completed related issues,” he mentioned.
Mebane examined the scientific literature on occasions like Wyoming deliberately poisoning the Green River within the Nineteen Sixties to kill carp or unintended prepare derailments. Some species returned in a 12 months, whereas others took longer. For aquatic invertebrates floating downstream, navigating via dams and swimming pools within the Snake is likely to be difficult, however Mebane is optimistic the species will ultimately recuperate.
“Nature abhors a vacuum,” he mentioned.
Find reporter Rachel Cohen on Twitter @racheld_cohen
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