An Introduction to Pond & Stream Life

Dayton 4-H Club General Meeting


The McCoy’s, longstanding and active members of Dayton 4-H, participate in market goat, market and breeding sheep as well as swine.  This evening Mr. John McCoy gave a presentation on pond and stream life.  Mr. McCoy knows his stuff, being the Director of Ecosystem Restoration for the Maryland Department of Natural Resources.


His aquarium samples included aquatic insects, mussels, salamanders, fish and frogs.  The highlight of his program was about “Aquatic Outlaws,” otherwise known as invasive, non-native species that displace and harm indigenous, native species.  He mentioned that he had to wear a helmet when motoring on the Illinois River, while Chinese silver carp jumped out of the water and all around his boat.


Mr. John showed us three species of problematic crayfish that are found in Maryland waters.  This is called the Rusty Crayfish (note the rusty-colored tail), which occurs in the Monocacy and Susquehanna watersheds.  This species has hitchhiked into Maryland in bait buckets and competes and displaces native crayfish.  It’s original range was historically confined to the Ohio River basin and five mid-western, central states.


The Red Swamp Crayfish is now found on the Maryland eastern shore, Potomac and Patuxent rivers, competing with and displacing our native crayfish.  The native, “original” range for the Red Swamp is the lower Mississippi River and Gulf coast.


The Virile Crayfish was actively molting (shedding it’s skin, note the one freshly shed front claw) and has become an established species throughout the Piedmont, occurring in the Susquehanna, Gunpowder, Patapsco, Patuxent and Potomac rivers and Deep Creek Lake.  This species native range is the Great Lakes and Hudson River.

In all cases, these three crayfish species compete and displace our endemics, reduce abundance and diversity of aquatic plants, mussels, insect larvae, snails, frogs, fish eggs and turtles.  Great program, thank you Mr. McCoy!

The following are two PDF file links that contain excellent Keys to Maryland Crayfish Identification:

invasiveCrayfishThreat keytothecrayfishesofmd_8_18_10