The Idaho State Department of Agriculture (ISDA) says a "small number" of quagga mussels have been detected in the Snake River, specifically in the Shoshone Falls pool, Pillar Falls, and behind the hydroelectric facility in the Twin Falls Reservoir. According to the ISDA, quagga mussels were first detected in the Snake River last September. A chelated copper treatment was applied, and while the ISDA says the treatment reduced the mussel population, in December, Idaho Fish and Game said the treatment caused high mortality in some fish species. Related: IDFG releases information regarding the impact of the quagga mussel treatment to fish populationThe ISDA plans for another treatment in the affected stretches of the Snake River. The ISDA adds that a temporary closure will be in place from Pillar Falls to Twin Falls Dam. Additionally, a temporary closure from Pillar Falls to Auger Falls will begin in mid-October for ISDA treatment. Access to the Snake River at Centennial Park remains open. Mandatory inspection and decontamination remain for all watercraft.