Macroinvertebrate study on Lake Riley

Aquatic Macroinvertebrate Study on Lake Riley

The Minnesota Department of Natural Resources (DNR) is undertaking an aquatic macroinvertebrate study in Lake Riley from 2025 through 2027. Aquatic macroinvertebrates are insects in their nymph and larval stages, snails, crayfish, and mussels that spend at least part of their lives in water. These animals play a large role in lakes and other aquatic ecosystems by recycling nutrients and serving as food for larger animals.

Where will the sampling sites be located?

There are four sampling sites located on the northern and eastern sides of the lake. See map for appoximate locations.

Map of macroinvertebrate sampling locations around Lake Riley with numbered points and nearby landmarks.

What will a sampling site look like?

At each sampling site, DNR staff has installed 3 to 4 plastic trays (takeout container sized) in less than 1 foot of water near the lakeshore. The trays are typically placed on undeveloped/natural shoreline and out of the way of boat traffic and other recreational use. The trays are wedged in sand to stay secure and have a piece of pink tape tied on the help researchers relocate the trays. Orange stakes (the kind placed along driveways in winter) also mark tray locations. During open water season, staff will pull and replace the trays every 1 to 2 months to collect data on macroinvertebrate diversity and quantity.

Plastic trays submerged underwater near the lakeshore. Pink flagging marks the trays. — Groups of plastic trays, marked with pink tape, will be placed in the sand in shallow water to monitor aquatic macroinvertebrate populations. Four sites of sampling trays will be distributed in Lake Riley from 2025-2027.

How long will the study last?

The study will take place 2025 through 2027. Staff will visit the trays every 1 to 2 months during the open water season. Additional studies are planned to occur every 1 to 3 years.