LIBERTYVILLE, Ill. (AP) — Ecologists say they've found several dozen shrimp in the Des Plaines River that aren't commonly found in the area.

The Lake County Forest Preserves said Thursday that ecologists spotted the Mississippi grass shrimp last summer. The Forest Preserves didn't confirm the find until last week.

At first they didn't recognize the inch-long shrimp because they're transparent.

The shrimp are the first of their species found in the county. The only other known populations in northeastern Illinois are in the Kankakee River and Otter Creek in Kane County.

Lawrence Page of the Illinois Natural History Survey says the shrimp usually live in cleaner streams. So their presence could be a good sign for the health of the Des Plaines River.