Invasive aquatic species discovered in Macomb County

Posted at 12:00 PM, Oct 26, 2020

MACOMB COUNTY, Mich. (WXYZ) — An invasive species has been detected along the Clinton River Spillway in Macomb County.

The county said water lettuce is a free-floating aquatic invasive plant on the state's invasive species watch list.

Water lettuce creates thick mats that reduce oxygen levels, block sunlight, and prevent growth of submerged vegetation which have a negative effect on fish and other aquatic species. Water lettuce leaves are grayish-green and occur in a circular formation that ranges from 1.5 - 18 inches across. The leaves are spongy, deeply veined, and covered in tiny hairs. The freely hanging roots are feathery and can reach up to 20 inches long. Water lettuce propagates when horizontal stems (stolons) are broken from a parent plant and thus can also be distributed by water recreation, fishing equipment, and other activities that can cut the plant into pieces.

During routine water quality monitoring in September, Clinton River Watershed Council (CRWC) staff identified a single water lettuce plant in the Clinton River Spillway. CRWC reported the sighting to the Midwest Invasive Species Information Network (MISIN) immediately after confirmation.

The Lake St. Clair Cooperative Invasive Species Management Area (LSC CISMA) followed up on the report and both organizations have continued to survey the area for additional plants resulting in the identification and removal of 115 individual plants.

"The Lake St. Clair CISMA was very quick in their response to the MISIN report,” said Eric Diesing, CRWC, watershed ecologist. “Invasive species can harm our local water resources in many ways and I am glad that we were able to catch this one early. This is a great example of effective teamwork and water quality monitoring. CRWC will continue to work with the LSC CISMA to address this issue into the future."