RAPID CITY, S.D. — A South Dakota Game, Fish and Parks report says a lake trout restock of a western reservoir is going well.
The fish were added to Deerfield Reservoir in 2015 to deal with an overabundance of rock bass, a smaller predatory fish, the Rapid City Journal reported .
Tagged lake trout and accounts from local anglers show that the fish have been able to survive and are adjusting to life in the reservoir, the agency’s report said.
The lake trout have been able to survive because of Deerfield’s size, depth, water temperature and oxygen level, said John Lott, the agency’s aquatic resources chief.
“At Deerfield one of initial concerns at the time of stocking was if the temperature and oxygen level in the summer period would be sufficient, and it was believed that lake trout would do OK there,” Lott said.
However, some of the fish are smaller in size, said Gene Galiant, the report’s author.
“We have seen condition declining in our fish, they are getting skinny, which is to be expected,” Galiant said. “These fish spent about 10 years living in a hatchery feeding on pellets and now they have to feed on a more natural diet of fish and insects, so they are getting pretty skinny on us right now and we’re watching that.”
Officials don’t plan to introduce any new predator species to the reservoir, Lott said.
“Lake trout are something that we want to evaluate and see how they do,” Lott said. “It’s very hard to evaluate a number of species at any one time, and another thought is we want to have a predator in there that will have the least amount of negative impact on anything that’s a positive in the lake.”