(LAUNCHING SUMMER 2026) AUBURN HILLS GEOCACHING CHALLENGE DECODER
Freshwater mussels are often preyed upon by an unlikely creature, the ________.
Fun Fact: Native freshwater mussels are environmental indicators, meaning their health and population is indicative of an ecosystem’s health. When the environment is good, they can live for over 50 years!
Common Name: Freshwater Mussels
Scientific Name: Unionidae
Size: 1 – 8 Inches
General Description & Behaviors:
Native freshwater mussels are found in rivers, streams, and lakes thought Michigan (we have 43 species in the state), like the one right in front of you! Freshwater Mussels have a very unique reproduction cycle as they release larva into the water which attach to the gills of fish. They mature on the gills then fall off to a permeant spot, allowing them to migrate. Some species have flaps which can be used as lures that look like small fish, invertebrates, or crayfish to lure fish near them. When the fish is near, they release a cloud of their larva, some even grab the fish and inject their larva into the gills of the host fish.
Why So Important:
Freshwater Mussels are a key link in the food chain between aquatic microorganisms they feed on, such as algae, and large animals that eat unionids like river otters. Live individuals and empty shells provide habitat for aquatic insects and crayfish. Mussels are useful water quality indicators as they are long-lived filter feeders who spend most of their lives within a small section of a stream.
What Is Being Done To Help Them & How Can YOU Help:
These important creatures have seen a drastic decline in the past century, 31 of Michigan’s 43 species are threatened or endangered. The many reasons for this include rising water temperatures, altered waterways, pollution, and invasive species. Barriers like dams can prevent them from migrating and decreases genetic diversity, hindering their recovery. As filter feeders they are often the first victims of pollution such as heavy metals and organic pollutants, which are common in Michigan Waterways. Invasive species like the zebra and quagga mussels kill native mussels by coating their shells, suffocating them, and competing for food. You can help by NOT disturbing, collecting, or killing mussels you find while out on the water; Washing all aquatic gear or boats and leaving them to dry overnight before transporting them to another water body. This prevents you from accidentally transporting invasive mussels; Preserving aquatic habitats by NOT destroying riparian zones, forests around waterbodies, and not dredging/altering rivers and streams.