Monitoring impact on fish population during treatment for quagga mussels

IDFG collecting information to be used before and after treatment
Idaho Fish and Game marking fish population with fin clip in quagga mussel abatement efforts
Posted at 2:02 PM, Oct 04, 2023

Idaho Fish and Game is using a tagging technique to monitor the impact of the quagga mussel abatement treatment on the fish populations in the Snake River.

On October 1-2, fisheries biologists from around the state used a non-lethal electrofishing technique to tag fish in three separate areas of the river.

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Two of these areas are near Centennial Park and the Shoshone Reservoir, where the quagga mussel larvae were detected. The other was downstream just inside the treatment area where they do not expect fish to be affected.

The tags are in the form of a fin-clip on the tail. The marks will be used to estimate the number of fish before and after the treatments, in turn helping IDF&G know where populations will need attention in the rebuilding process.

Losses in the fish population are expected, though the IDFG has plans in place to help mitigate the loss and rebuild a healthy population. Options they will use include translocating adults after the treatment, hatchery stocking, and natural recolonization from downstream.

The abatement, using a chelated copper treatment approved by the Idaho State Department of Agriculture, is the first of its kind in these waters.

Proactively implementing tools to monitor what will happen to the river's fish population will also provide knowledge to develop a plan for the best course of action moving forward, as well as if/when faced with the infestation again.

The abatement efforts were scheduled to begin on October 3.

More information about the quagga mussels impacts on Idaho's fish and wildlife resources can be found on the Idaho Fish and Game website.