(Pennington County, SD) — South Dakota wildlife officials and the U.S. Bureau of Reclamation say zebra mussels have been found in Pactola Reservoir in Pennington County. Officials say analysis of a water sample taken by the federal agency determined that zebra mussel larvae were present in the reservoir. South Dakota Game, Fish, and Parks says boaters should clean all watercraft and trailers, remove aquatic plants and mud and drain all water. Zebra mussels’ size can range from microscopic to two inches in length.