Predators and a missing link may be slowing the invasion of zebra mussels in Lake of the Ozarks. The Missouri Department of Conservation has been tracking the progression of the invasive species since it was introduced to the lake several years ago.
Until recently, the zebra mussel population was reproducing rapidly, causing concerns about the long term impact of the species. That may be slowing down as the mussels reproduction appears to have peaked and several species of native fish which usually feed on shad seem to prefer the zebra mussel or “junk food” as it is often referred to, according to Greg Stoner, a fisheries biologists with the Missouri Department of Conservation. “The blue cat and drum are feeding on the adult mussels that usually reach a maximum size of about inch in length,” he said. “So far the blue cat and drum seem to be the only fish that made the switch. The zebra mussel has little nutritional value compared to shad.”
The change in feeding patterns of the two species of fish may or may not have any impact on growth rates. That will take several years to determine, Stoner said. Blue cats are a popular catch for fishermen. The species can grow to over 100 pounds. Drum are not as popular.
There is also an indication that some areas of the lake where there were higher numbers of zebra musssels are reporting fewer infestations. Reports from the Gravois Arm and closer to Bagnell Dam, where heavy infestations have been reported, indicate there weren’t as many during the annual winter drawdown compared to 2008, Stoner said. “When an invasive species moves in there is often a population explosion,” he said, “they fill a niche not being being filled by a native species, but in time they overshoot the carrying capacity of the environment. Something is missing that slows down their reproduction.”
Source: Lake Sun