Thursday, October 26, 2017

Endemic Fishes of the New River, by Don Orth

Anyone who travels in the New River valley know it’s a very special place.  Those who study the fishes know some secrets too.   The New River is the oldest major stream in the eastern United States – it should be the Old River.  The historic Teays River originated in the Tertiary Period and at that time drained much of eastern North American in the pre-glacial period.  However, the original route of the ancient Teays was altered by glacial advances which created a massive ice dam blocking the northward-flowing Teays. Geologists maintain that the river retained its course from headwaters in the Blue Ridge province, across the Valley and Ridge province and into the Appalachian plateau for 100 million years or more.  Through this period of slow uplift of the Appalachian region the river continued to slowly erode its bedrock streambed through gaps in major mountain ranges.  This wide, shallow, bedrock river flows northward across the strike or grain of underlying geological structures (Spotila et al. 2015).

New River supports 46 native fishes, 8 of which are endemic species.  Endemic species are unique to a defined geographic location.  The endemic fishes of the New River likely diverged after geographic isolation from ancestral forms 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.  This history explains why the number of native fish species in the New River is low compared with similar sized rivers in the eastern US.  However, the number of endemic species is high.    
New River near Rich Creek, Virginia.  Photo by Valerie F. Orth. 
New River has a relatively high number of endemic fishes due to two main causes: (1) the presence of natural barriers and (2) the immobility of a species.  The Pleistocene glaciers did not reach Virginia though the climatic and barrier effect was a strong influence in the New River fish fauna.  During the Pleistocene, the climate cooled and for fish in the New River, it was “no way out and no way in.”  New River fish had to stay, adapt, or die.  The mainstem falls, cascades, rapids prevented upstream dispersal after the Pleistocene glaciation.   The Pleistocene ended 10,000 years ago, leaving many native New River fishes as cool-adapted.  Few native warmwater species are widespread.   Today, the New River has the highest proportion of introduced to native fishes of any eastern USA drainage as at least 57 introduced fishes persist in the New River alongside 44 native fishes (Easton et al. 1993; Easton and Orth 1994; Angermeier and Pinder 2015; Hilling in press).     

The eight endemic fishes include three minnows, two sculpins, and three darters, all groups that typically have little or no long-range migrations. The first three endemic fishes are in cyprinids.  Cyprinids are members of the family Cyprinidae (minnows), the most species rich family of fishes in North America.  There are 53 recognized genera and 286 species of minnows in North America (Mayden 1991).

The Bigmouth Chub Nocomis platyrhynchus occurs only in the New River drainage and its distribution is allopatric with its closest relatives, the River Chub Nocomis micropogon and the Bull Chub Nocomis raneyi.  Bigmouth Chub inhabits medium- to large-sized tributaries and the mainstem New River which have a moderate gradient, warm, usually clear water, and a good mix of gravel to boulder substrates.   For more information, click here.
Bigmouth Chub male (top) and female (bottom). Photos by Hunter Hatcher (top) and D. J. Orth (bottom) 
The Kanawha Minnow Phenacobius teretulus is one of five species of Phenacobius referred to as suckermouth minnows for obvious reasons.  The Kanawha Minnow is the only Phenacobius in the New River, has a limited distribution, and is an uncommon part of the fish assemblage.  Juveniles and adults typically occur in riffles and runs of gravel, rubble, and boulder in cool to warm creeks and small to medium rivers.   For more information, click here. 
Kanawha Minnow.  Photo by Fritz Rhode.
New River Shiner Notropis scabriceps occurs in pools and slow runs of cool to warm creeks and small to medium rivers. It is more common in Blue Ridge province than in the Appalachian or Ridge and Valley provinces.  As with other New River endemics, temperature has been postulated as a major factor governing its distribution.  In one of the few temperature preferenda studies, the final thermal preference of the New River Shiner was 19.3 °C, or 66.7 °F (Shingleton et al. 1981).   Two non-native species, the telescope shiner Notropis telescopus and whitetail shiner Cyprinella galactura may also compete with the New River Shiner (Keplinger 2007).
New River Shiner.  Photo by Ben A. Cantrell.
Kanawha sculpin Cottus kanawhae was first considered a subspecies of the Banded Sculpin Cottus carolinae.  It is widely distributed in tributaries of the New River and often overlaps with the Mottled Sculpin Cottus bairdi.  Why?  I don’t know.
Kanawha Sculpin.  Photo by Derek Wheaton.  
Dorsal saddles of Kanawha Sculpin.  Photo by D.J Orth. 
Dorsal fin of Kanawha Sculpin. Photo by D.J.Orth
Bluestone sculpin Cottus sp. has a very limited distribution in the Bluestone River and little is known about its present status and distribution.   
Bluestone Sculpin.  Photo by Noel M. Bulkhead.  
Candy Darter Etheostoma osburni is a rare fish that’s currently under review for federal listing as an endangered species. Candy Darters are most abundant in shallow riffle and run habitats but only occurs in a limited number of streams and has declined or disappeared from some historic locations.   The proposed Mountain Valley pipeline would cross Big Stony Creek, which supports one of the remaining populations of Candy Darters.  The Candy Darter may be the most colorful local darter.  It’s occurrence in clear mountain streams means it can be seen by the avid snorkeler willing to crawl amidst the fast-flowing boulders and cobbles. Click on this video link to watch the Candy Darter behavior underwater. 

Candy Darter male.  Photo by Derek Wheaton.
Kanawha Darter Etheostoma kanawhae is a close relative of the Candy Darter and the two distributions do not overlap.  Kanawha Darter occurs in fast-flowing riffles in tributaries of the New River in North Carolina and Virginia.    Their ancestral form was likely widely distributed in the Teays and Old Mississippi rivers and separated by the Pleistocene glacial advance.  Other close relatives occur in the Ozark highlands and the upper Ohio drainage. 
Kanawha Darter male. Photo by Noel M. Burkhead. 
Appalachia Darter Percina gymnocephala is one of the rare, endemic darters of the New River.  Although it has no special state or federal status, its distribution and status has never been evaluated.    For more information,  click on this link.    Not much is known about the Appalachia Darter and its life history.  It's safe to say that as a New River endemic it's adapted for cool water and inhabits cobble and boulder habitats.  
Appalachia Darter.  Photo by Isaac Szabo. 
One cannot discuss the percid fishes of the upper New River without a mention of the Walleye Sander vitreus.  Jenkins and Burkhead (1994) considered the Walleye to be an introduced species.  However, a genetically unique walleye was discovered in the New River and is the basis for a restoration effort (Palmer et al. 2007).  Jenkins and Burkhead relied on the fact that there were no reports of Walleye by 19th century investigators (Cope 1868 paper) and the Virginia Fish Commission.  However, no targeted investigations were ever done and intensive stocking of Walleye in Claytor Lake began after 1939.  These introductions were traceable to Lake Erie and Hudson bay stock.  Work is now underway in the Hallerman Genetics Lab at Virginia Tech to examine and continue marker-assisted selection.  The unique walleye strain is a river-spawning Walleye and may have adaptive traits that permit it to survive better in the New River.  They grow to large size (see photo). 
Historic state record Walleye from the New River.  22 pounds and 8 ounces.  
The endemic fishes of the New River are unique and their limited distribution means many anthropogenic activities may have a disproportionate influence on species viability.  The construction of dams on the mainstem New and its tributaries fragmented populations and eliminated coolwater habitats. In addition to hydropower dams, emerging threats include introduction of nonnative species and climate change (Angermeier and Pinder 2015).  New River is a special place for people – and now you know why its special for fishes.  

Angermeier, P.L., and M.J. Pinder. 2015.  Viewing the status of Virginia’s environment through the lens of freshwater fishes.  Virginia Journal of Science 66(3). Article 2   
Cope, E.D. 1868.  On the distribution of freshwater fishes in the Allegheny region of southwestern Virginia. Journal of the Academy of Natural Science of Philadelphia, Series 2, 6, part 3, article 5 (1869):207-247.
Easton R.S. and D.J. Orth D.J. 1994. Fishes of the main channel New River, West Virginia. Virginia Journal of Science 45: 265–277.
Easton R.S., D.J. Orth, and N.M. Burkhead. 1993. The first collection of rudd, Scardinius erythrophthalmus (Cyprinidae), in the New River, West Virginia. Journal of Freshwater Ecology 8:263–264.
Hilling, C.D., S.L.Wolfe, J.R. Copeland, D.J. Orth, E. M. Hallerman. In press.  Occurrence of Two non-indigenous catostomid fishes in the New River, Virginia. Northeastern Naturalist
Jenkins, R.E. and N.M. Burkhead. 1994. Freshwater fishes of Virginia. American Fisheries Society, Bethesda, Maryland.
Keplinger, B.J.  An experimental study of vertical habitat use and habitat shifts in single-species and mixed-species shoals of native and nonnative congeneric cyprinids.  Masters thesis, West Virginia University, Morgantown.
Mayden, R.L. 1991.  Cyprinids of the New World.  Pages 240-263 in I.J. Winfield and J.S. Nelson, editors. Cyprinid Fishes: Systematics, Biology and exploitation.  Springer, Dordrecht
Palmer, G.C., J. Williams, M. Scott, K. Finne, N. Johnson, D. Dutton, B.R. Murphy, and E.M. Hallerman, 2007. Genetic marker-assisted restoration of the presumptive native walleye fishery in the New River, Virginia and West Virginia. Proceedings of the Annual Conference of the Southeastern Association of Fisheries and Wildlife Agencies 61:17-22.
Shingleton, M.V., C.H. Hocutt, and J.R. Stauffer, Jr. 1981.  Temperature preference of the New River Shiner.  Transactions of the American Fisheries Society 110:660-661.
Spotila, J.A., K.A. Moskey, and P.S. Prince.  2015.  Geologic controls on bedrock channel width in large, slowly-eroding catchments: Case study of the New River in eastern North America.  Geomorphology 230:51-63.