COLO, Iowa – The Iowa Department of Natural Resources (DNR) and Story County Conservation (SCC) plan to start drawing down Hickory Grove Lake near Colo in early May to remove common carp. The lake will remain drained until fall.
In 2019, SCC and the DNR partnered to remove carp from Hickory Grove Lake by draining as much of the lake as possible. “Post draw-down netting suggested that we had successfully eliminated the carp,” said Ben Dodd, Iowa DNR Fisheries biologist. “Unfortunately, we observed several adult fish last week as the lake was refilling. Complete eradication of an undesirable species from a lake and its watershed is a difficult task, but we’re developing a new plan to complete the job.”
Hickory Grove Lake is a popular outdoor recreation destination in Story County, boasting a variety of activities including swimming, paddling, boating, watching wildlife and angling. Water quality in the lake has declined since the early 2000’s, due to nutrient and sediment pollution and a large population of common carp. In recent years, carp have become so abundant in Hickory Grove Lake that they eliminated aquatic plants from the lake.
Common Carp is an invasive fish species that negatively impacts water quality and sport fish populations in Iowa lakes. They uproot and destroy aquatic plants when they feed. Sediment and nutrients are also resuspended into the water column during this process, which can lead to increased undesirable algae blooms.
SCC and DNR recently partnered to improve water quality and recreational opportunities at Hickory Grove Lake through a variety of lake restoration practices, including shoreline deepening and armoring, revamping the beach and campground area of the park, dredging the eastern portion of the lake, making improvements to the dam and lake outlet structure, and installing a variety of fish habitat structures