Snake River Quagga Mussel update
An ID license plate that was submerged in Lake Mead for 9 months emphasizes the rate at which these species can reproduce and take hold. Photo Credit: Spokesman-Review
As the Idaho State Department of Agriculture reported recently, Quagga mussels were discovered in the Snake River near Twin Falls on September 18th, 2023. This discovery is incredibly troubling and carries the potential for drastic environmental consequences for not only the Snake River but the entire Columbia Basin if these mussels are allowed to become established.
Quagga mussels, like other invasive species, drastically outcompete their natural counterparts. Originally from Europe, these mussels were first discovered in the Great Lakes where they were likely transported via the ballast water of international cargo ships. With incredibly rapid reproduction rates, we’ve seen these mussels take hold and change the ecosystems of nearly every waterbody to which they have been introduced. Until this discovery in the Snake, the Columbia River basin was the only major river system in the United States that had not seen these invasive species introduced.
Zebra and Quagga Mussel distribution throughout the United States - USGS
Quagga Mussels are filter feeders meaning that they scour the aquatic environments of plankton populations. This can lead to cascading effects on other organisms and established food chains, disrupting the other species that are dependent on lower trophic levels. This can lead to an increased presence of toxic algal blooms by removing species of plankton and allowing toxic algae to proliferate.
Adult mussels can produce 30,000 to 1,000,000 veligers, or lava, per year. Once established in an ecosystem, these veligers will move downstream or throughout the water body making an aggressive approach necessary to ensure that their spread is contained. In areas that have seen these mussels take hold, it has been reported that they can reach a density of up to 8,000 mussels per square meter.
In addition to the environmental concerns, these mussels attach themselves to hard surfaces, such as rocks, boats, docks, pipes, and water infrastructure. Their prolific growth can clog pipes and lead to extraordinary maintenance problems and costs. It has been estimated that it costs over $500 million (US) per year to manage mussels at power plants, water systems, and industrial complexes, and on boats and docks in the Great Lakes. Considering the volume and of infrastructure in the Snake and Columbia Basin at large, the discovery of these mussels represents an incredible economic threat to our region.
Considering the gravity of this situation, the Idaho State Department of Agriculture (ISDA), the State agency leading the response, moved forward to chemically treat the area of detection with a copper compound known as Natrix. This product is toxic to fish and other aquatic organisms and will result in the mortality of fish, vegetation, and shellfish in the 6-mile treatment area. It is unknown how far downstream this mortality will reach as the compound is continually diluted.
While this impact is not ideal, the risks of not acting aggressively pose a far greater threat to the Basin at large. Moving forward, we hope that this initial treatment and fast action by the State will eradicate these known invasives and serve as a reminder of how important our current detection and deterrents are for the health of the region.
If you’re a boater, or just have driven across the state, you have likely seen or stopped at a watercraft inspection station. This initiative, while seemingly rather benign, is a major reason that we have not been faced with this crisis earlier. Since 2009, over 1 million inspections have been conducted in Idaho that resulted in 413 mussel-fouled watercraft being stopped and decontaminated.
If you, or someone you know, has recently had a watercraft in the Snake River near Twin Falls, be sure to have your vessel inspected and hot-washed at one of the public locations that can be found on the ISDA response page.
With climate change and other stressors already pushing the Columbia Basin out of equilibrium, we must remain vigilant and do all that we can to keep these invasive species from taking hold.