Deer Creek Report and fish ID Question

Type: Chesapeake
Region: Northern
Location: Deer Creek

My wife and I fly fished Deer Creek above the Stafford Road Bridge early Monday morning, finding it full but fishable. For the first half-hour or so, she and another spinfishing angler (apparently of some note locally) caught numerous hickory shad early on, while I got only the occasional bump. Somehow she neglected to pass on that she had added a five foot sink tip, three big split shot, and a heavier fly! To her credit she eventually did insist I take her rod and spot, although she may have already worn it out! I got a few before moving further upstream, where by virtue of getting the fly down (snagging often) I was able to redeem myself. There's a lesson in there somewhere.

A few hours later while wading across to depart, my line was left to trail downstream and I felt a bump. When I lifted the rod I found myself fast to a fair sized common carp. On last year's annual pilgrimage to Deer Creek, I had another, larger common carp (I prefer to call them 'golden shad') which also took quite some time to subdue. It likewise intercepted a swung fly intended for hickories, which I've had happen nowhere else in many years of keeping hooks wet.

Before departing, we took a look from the bridge, below which we saw about a dozen rather large (maybe #10), rather dark-backed, blocky/chubby cyprinids right under the strongest flows, many directly above the largest boulders. These fish held higher in the water column than one would expect a common carp to do, and notably had distinctly dark pelvic and pectoral fins (with some lightening of the distal margins apparent). Since we could also clearly ID a specimen of common carp off to the side in 'softer' flows for comparison, we were debating what the other fish might have been.

Guessing it might be a buffalo on the way home to western MD, I googled 'bigmouth buffalo susquehanna river maryland' and found a report about anadromous fishes of the Susky, prepared by the USFWS. At the very end was a mention of bigmouth buffalo among other species that were collected, so I thought that might actually be a possibility. Then today I did some more searching online and found a USGS distribution map for that species which does NOT indicate they are present in MD, although apparently some escaped from a VA hatchery and have been found there in limited fashion. Its hard to imagine this fish of large inland rivers making its way to Deer Creek, but its not a lot easier to imagine snakeheads appearing near the head of the bay either.

So, what is the known status of bigmouth buffalo in MD? If someone were to go and look downstream off that bridge in the near future, these fish might very well still be observable. HJS (from Tidalfish.com) suggested quillback carpsucker as a possible ID, but the dorsal fin shape was very much like that of the common carp, and not exaggerated like that of a quillback. Any ideas then what my wife and I saw?

DNR's reponse (Contributed by Joseph Love, PhD)
The picture you supplied is of a common carp. To get to the rest of your posting: Bigmouth and smallmouth buffalo in the Mid-Atlantic should be confined to the Carolinas in the Mid-Atlantic. The species may have been Quillback, or perhaps fallfish. The Quillback has a body shape more like carp, but the first few spines of the dorsal fin are slightly longer than those of a common carp. They are not as long as the closely related highfin carpsucker, which are also found in the Carolinas. There are other species that may superficially resemble buffalo, such as shorthead redhorse and white sucker that resemble fall fish, but none of those have a deep body like carp or quillback. I suppose the fish could have also been gizzard shad, though those definitely aren�t cyprinids.