Invasive algae, mud-snail varieties found in Michigan rivers

The Michigan Department of Environmental Quality (DEQ) and Department of Natural Resources (DNR) confirmed the presence of didymo, a freshwater alga, and New Zealand mud snails -- two new invasive species -- in Michigan rivers this week.

Didymo, also called rock snot, was found in the St. Mary’s River near Sault Ste. Marie. The alga isn’t a public health threat, but it is damaging to aquatic habitats. Thriving in cold, clean water, didymo grows along river bottoms in thick mats and can smother environmentally critical aquatic life, including healthy algae and invertebrates.

New Zealand mud snails also pose a risk to native species, especially to other snails and macroinvertebrates. The snails are only 1/8-inch long and are extremely resilient, living in damp conditions for up to 26 days, which makes them easily transportable. New Zealand mud snails were found near Ludington, in the Pere Marquette River.

These species can be easily spread to new environments via fishing and wading equipment, as well as other hard surfaces. The DEQ and DNR remind boaters and anglers to follow state regulations when cleaning their equipment and vessels.