During stream monitoring this past summer, Nick Huber and other ecologists of the Lake County Forest Preserves discovered several dozen Mississippi grass shrimp, Palaimonetes kadikensis, in a forest preserve along the Des Plaines River in southern Lake County. Due to the fact that you can see right through them, this species is also commonly referred to as glass shrimp. At first sight, the ecologists did not recognize the inch-long crustaceans. It was clear that this find was something rare and exciting. After further collection parameters were determined, Huber and his team confirmed it was safe to remove two specimens for identification in their laboratory. Aquatic insect identification requires equipment with high-powered magnification to count tiny body parts nearly invisible to the naked eye. It wasn’t until last week that the shrimp were officially identified and documented. This is the first documentation of the species in Lake County, Illinois.
This is a rare find for northeastern Illinois. The only other known locations are in the Kankakee River and Otter Creek in Kane County. According to Lawrence M. Page of the Illinois Natural History Survey, “Palaemonetes kadiakensis almost always is associated with, and is most abundant in, living aquatic vegetation. Its reduction in distribution and abundance in Illinois is probably attributable to increased turbidity and sedimentation and the resultant loss of vegetation.” Therefore, this find is also very encouraging, as Mississippi grass shrimp are indicative of cleaner water systems. Their presence holds promise for the improvement of aquatic habitats within and surrounding the Des Plaines River.
—The Lake County Forest Preserves provided this information.