In an earlier post I misidentified this lamprey as an American Eel. I’d like to make the correction here.
On a hike along a stream (Maryland USA / March 2010) we found several brook lampreys swimming around. There are three species of lampreys in Maryland: Sea Lamprey, Least Brook Lamprey, and American Brook Lamprey. This one is a Least Brook Lamprey or an American Brook Lamprey. Both or these brook lampreys are non-parasitic. Sea lampreys use their disk shaped mouth to attach themselves to fish and drink their bodily fluids and blood. Brook lampreys do no do this. I believe we came across some lampreys spawning. After they spawn they die soon afterward.
You can find some interesting things out there!