In 2011, USGS researchers began studying Lake Erie's fish and seasonal hypoxia across a multi-year project. 15 years later, the findings showed fish crowding areas near 2–3 mg/L oxygen, revealing an unexpected shift at the edges of low-oxygen zones

Lake Erie's dead zones aren't driving fish away. Instead, fish are crowding right along the edge. A major USGS study reveals a surprising shift. Yellow perch and smelt stack up near 2–3 mg/L oxygen boundaries. They stay in cool water and hunt easy prey. Scientists call this habitat compression. It completely redefines how we track fish across the Great Lakes.

Why Lake Erie develops oxygen-depleted water