MILTON, Vt. (AP) — The Vermont Department of Fish and Wildlife says thousands of alewives were found dead on the shores of Lake Champlain as the ice clears after the long winter.

Alewives are a species of herring native to the Atlantic Ocean that spawn in freshwater tributaries. They were first discovered in Lake Champlain in 2005. On average, they are about 10 inches (25 centimeters) long.

Vermont Fish biologist Shawn Good says alewives are highly susceptible to fluctuations in water temperature. When the ice clears in the spring, thousands of dead fish can wash up on shore. The die-offs are a common spring occurrence.

Despite the die-off, Good says alewives are firmly established in Lake Champlain.

He says their presence highlights the danger posed by invasive species being introduced into the lake.