Friday, October 2, 2015

Kanawha Minnow, a rare endemic minnow of the New River, by Don Orth

The Kanawha Minnow is in the genus Phenacobius.  This name means  “deceptive life."  It is a deceptive fish for two reasons.   First it tends to be misidentified as a sucker and resembles an herbivorous fish.   Most novice fish collectors will initially consider it a juvenile sucker (Catostomidae) unless they look very closely.  Yet it is a minnow (Cyprinidae) and not a sucker.   This deception was first evident when it was described by E. D. Cope (1867); he observed that the “alimentary canal was not longer than head and body,” whereas herbivorous fishes have long guts.   Furthermore the form of pharyngeal teeth indicated that this fish was carnivorous.   Pharyngeal teeth are the teeth located on the pharyngeal arch of the throat of minnows and suckers.   These fish have lack teeth on the jaws so these specialized teeth occur in the back of the throat to process food items.  Pharyngeal teeth of the Kanawha Minnow have a hooked shape and are sharp; they are not the grinding surfaces of an herbivore.    
  Illustration by Filipa Filipe
The genus, Phenacobius, is commonly referred to as the suckermouth minnows and includes 5 species.   The most widely distributed is the Suckermouth Minnow Phenacobius mirabilis, which occurs in the Mississippi drainage and some east Texas basins.  The other species, however, all have limited distributions.  In Virginia, you may encounter the Suckermouth Minnow only in Big Sandy drainage, whereas the Fatlips Minnow (P. crassilabrum) occurs in the Powell, Clinch, and Holston, and the Stargazing Minnows (P. uranops)  occurs only in the South Fork Holston.  The other species, the Riffle Minnow (P.  catostomus) occurs only in Alabama, northwestern Georgia, and southeastern Tennessee. 
Close up, lateral view of  Suckermouth Minnow Phenacobius mirabilis.   Photo by Dick Biggins, U.S. Fish and Wildlife Service, Licensed under Public Domain via Commons

The mouth of Phenacobius is very small and located in the inferior position.  Therefore you have to examine it from a ventral view to see its structure.   Cope described the maxillary arch as “projectile” and it is covered by thick fleshly papillose lips.   The diet is dominated by immature midges, blackflies, caddisflies, and mayflies.   In the photo below you can see the fleshy lips and enlarged posteriorly and behind the mandible.  They feed on immature insects in benthic zones of fast velocity. 

Ventral view of mouth and anterior of Kanawha Minnow.

The Kanawha Minnow is a coolwater fish endemic to the New River drainage. The name “Kanawha”  refers to the upper Kanawha (or New) River drainage.   The species is found rarely at in the upper reaches of  New  River drainage, North Carolina, Virginia, and West Virginia. It may be more common in the Blue Ridge Province.   It likely diverged after geographic isolation from the ancestral form during the Pleistocene glaciation.    These glaciers, as they advanced southward, displaced fishes into unfrozen tributaries.  The upper New River drainage was likely an important refugia for fishes during this most recent ice age.  


Distibution of Kanawha Minnow in New River of NC, VA, and WV (from Lee et al. 1980)
Like many rare minnows, the distribution and status of populations of Kanawha Minnow are not rigorously examined.    Chipps et al. (1993), in a survey of 55 stations, found the Kanawha Minnow at 4 stations and captured fewer than 100 specimens.   East Fork of Greenbrier River was reported to be most abundant population. There were 71 map locations that indicate the Kanawha Minnow is widely distributed in the upper New River and its tributaries draining the Blue Ridge physiographic province in North Carolina and Virginia (Menhinick 1991; Jenkins and Burkhead 1994).    Hamrick et al. (1975) wrote that the species avoids tributaries of in the Ridge and Valley province.   The vast majority of collections of the Kanawha Minnow consist of fewer than 10 specimens.     Collection records indicate that juveniles and adults typically occur in riffles and runs of gravel, rubble, and boulder in cool to warm creeks and small to medium rivers.      

The species was listed as threatened in North Carolina in the past due to the proposed two-dam pumped storage project, which would have flooded much of its prime habitat.  Appalachian Power Company, an operating company of the American Electric Power Company, fought for over ten years for the right to construct a massive, two-reservoir pumped-storage hydroelectric facility stretching from Grayson County, Virginia, into the North Carolina counties of Ashe and Alleghany.   For more information click here.      

Chipps, S.R., Perry, W.B. and Perry, S.A. 1993. Status and distribution of Phenacobius teretulus, Etheostoma osburni, and "Rhinichthys bowersi" in the Monongahela National Forest, West Virginia. Virginia Journal of Science 44:47-58.

Cope, E.D.  1867. Description of a new genus of cyprinoid fishes from Virginia.  Proceedings of the Academy of Natural Sciences of Philadelphia.  19:95-97.

Hambrick  P.S., R. E. Jenkins and J. H. Wilson. 1975.   Distribution, habitat and food of the cyprinid fish Phenacobius teretulus, a New River drainage endemic.  Copeia 1975:172-176.

Jenkins, R.E., and N.M. Burkhead.  1994.  Freshwater fishes of Virginia.  American Fisheries Society.  Bethesda, Maryland.  1079 pp.

Lee, D.S., et al.  1980. Atlas of North American Fishes.  Publication #1980-12 of the North Carolina Biological Survey. North Carolina State Museum of Natural History.  853 pp.

Menhinick, E.F. 1991.  The freshwater fishes of North Carolina.  North Carolina Wildlife Resources Commission.  227 pp.

NatureServe. 2013. Phenacobius teretulus. The IUCN Red List of Threatened Species 2013:e.T16957A19034012.

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