Aquatic invasive species—which ones to watch for, how to stop them, and why—are the focus of “Stop Aquatic Hitchhikers!” from 2–3 p.m. Tuesday, July 9, at Lakeside Chautauqua on the Marblehead peninsula. It’s part of a summer series of Lake Erie science talks presented by staff from Ohio Sea Grant and Stone Lab. Admission to the talk itself is free but requires paid admission to Lakeside and a pass to park there. Learn more. (Photo: Invasive round gobies, Dave Jude, Michigan Sea Grant, via Flickr.)