MILWAUKEE (AP) — A new study by the University of Wisconsin-Madison highlights the hefty cost of controlling aquatic invasive species in the state’s lakes. The study found that the estimated cost of controlling a single invasive species, the spiny waterflea, in just one lake could range from $86.5 million to $163 million over 20 years. Researchers say the study’s results show that a broader measure of the costs of controlling aquatic invasive species should be taken into account. The spiny waterflea turned up in the Madison lakes of Mendota and Waubesa in 2009. It now inhabits at least 22 waterways in Wisconsin. The state Department of Natural Resources say there are 37 types of invasive species in inland lakes.