Southeastern Fishes Council Proceedings Volume 1 Number 52 Number 52 (December 2010) Article 3 12-1-2010 Comparative Conservation Genetics of Two Endangered Darters, Percina rex and Percina jenkinsi Anna L. George David A. Neely Richard L. Mayden Follow this and additional works at: https://trace.tennessee.edu/sfcproceedings Part of the Marine Biology Commons Recommended Citation George, Anna L.; Neely, David A.; and Mayden, Richard L. (2010) "Comparative Conservation Genetics of Two Endangered Darters, Percina rex and Percina jenkinsi," Southeastern Fishes Council Proceedings: No. 52. Available at: https://trace.tennessee.edu/sfcproceedings/vol1/iss52/3 This Original Research Article is brought to you for free and open access by Volunteer, Open Access, Library Journals (VOL Journals), published in partnership with The University of Tennessee (UT) University Libraries. This article has been accepted for inclusion in Southeastern Fishes Council Proceedings by an authorized editor. For more information, please visit https://trace.tennessee.edu/sfcproceedings. Comparative Conservation Genetics of Two Endangered Darters, Percina rex and Percina jenkinsi This original research article is available in Southeastern Fishes Council Proceedings: https://trace.tennessee.edu/ sfcproceedings/vol1/iss52/3 Comparative Conservation Genetics of Two Endangered Darters, Percina rex and Percina jenkinsi ANNA L. GEORGE 1,2* , DAVID A. NEELY 1, AND RICHARD L. MAYDEN 2 1Tennessee Aquarium Conservation Institute, 1 Broad St., Chattanooga, TN 37402 USA; 2Department of Biology, St. Louis University, St. Louis, MO 63103 USA *Corresponding author: [email protected] ABSTRACT tats, the Ictaluridae and Percidae, have disproportionately higher percentages of jeopardized species than other Within the logperch group, a clade of 10 darter species southeastern fish families (Etnier and Starnes, 1991; from North America, two species are afforded federal pro - Etnier, 1997). tection. Percina rex is found in four major systems of the Within the family Percidae, darters are a clade of over Roanoke and Chowan river drainages, and Percina jenkin - 200 species of smaller-bodied fishes endemic to eastern si is restricted to less than 45 river kilometers of the North America (Song et al., 1998; Sloss et al., 2004). While Conasauga River. Two complete mitochondrial genes, the relationships within this group have been the subject NADH dehydrogenase subunit 2 and cytochrome b, were of considerable debate (Near, 2002; Sloss et al., 2004; Lang sequenced to assess genetic diversity and conservation sta - and Mayden, 2007), one group consistently recovered is a tus of these two species. Levels of haplotype diversity were clade of logperches of the genus Percina , subgenus higher in P. rex (h = 0.919) than P. jenkinsi (h = 0.889), but Percina (Near, 2002). The 10 described species of logperch nucleotide diversity was higher in P. jenkinsi (p = 0.00485) are ideal for comparative conservation genetics studies than P. rex (p = 0.00367). Four haplogroups were recov - due to their rapid diversification rates (Near and Benard, ered in P. rex , and two distinct clades of haplotypes were 2004) and a broad disparity in rarity and abundance, from recovered from phylogenetic analysis of P. jenkinsi . These extremely common and broadly distributed taxa to criti - results are interpreted as reflecting differing causes of cally rare and localized endemics. The clade is character - decline for the two logperch species: recent geographic ized by an elongate and conical snout, a pigmentation pat - fragmentation with subsequent bottleneck events in P. rex tern consisting of tiger-stripe bars, and the behavioral versus a historical bottleneck of the restricted P. jenkinsi . synapomorphy of rock-flipping. Individuals use their coni - Within P. rex , a combination of natural isolation of subpop - cal snout to turn over rocks and gravel to prey upon hiding ulations in different tributary systems and recent anthropo - macroinvertebrates (Jenkins and Burkhead, 1994), a morphic fragmentation of the drainage is likely responsible behavior unique among darters. Because this feeding strat - for observed patterns of differentiation among the extant egy requires nonembedded gravel or cobble substrates, populations. Percina jenkinsi is at far greater risk of logperch are negatively affected by siltation (Rosenberger extinction, and both the species and its habitat are in need and Angermeier, 2003). The two basal most species in this of immediate conservation actions. group, Percina rex (Jordan and Evermann) and Percina jenkinsi Thompson, are the only two in the subgenus list - INTRODUCTION ed as Federally Endangered (Near, 2002; Near and Benard, 2004; George et al., 2006). Aquatic vertebrates are imperiled at rates twice as high Percina rex , the Roanoke Logperch, was described as terrestrial species (Richter et al., 1997). Drainages of the from the upper Roanoke River in 1889 (Jordan, 1889), but southeastern U.S. contain a particularly diverse and imper - not widely considered a valid species until the late 1960s iled ichthyofauna (Master, 1990; Burr and Mayden, 1992; (Jenkins and Burkhead, 1994). Until 2006, P. rex was only Lydeard and Mayden, 1995; Warren et al., 2000). Etnier known from four river systems in Virginia (Fig. 1; Jenkins (1997) identified the top three causes of imperilment of and Burkhead, 1994). Three of these systems, the this fauna to be nonpoint-source pollution, alteration of Roanoke, Pigg, and Smith rivers (Roanoke River water flow, and small native range. Fishes with habitat drainage), are separated from the fourth, Nottoway River preferences of medium-sized rivers are disproportionately (Chowan River drainage), by Albemarle Bay. This disjunct affected. While these habitats support only 20% of south - distribution has been invoked as evidence for the loss of eastern fish species, they contain 40% of the fishes consid - many populations across the Piedmont physiographic ered imperiled from all habitats (Etnier, 1997). Two fami - province over the past 150 years (Jenkins and Burkhead, lies of fishes exhibiting close associations with these habi - 1994). This hypothesis was supported through the recent 1 December 2010 George et al. – Genetic Diversity in Two Endangered Logperch discovery of P. rex in several other systems of the Roanoke 1960s, caused one of the largest extinction events in the River drainage: Goose Creek and Big Otter River in the United States when at least 39 species of mollusks were middle Roanoke River and Mayo River and downstream lost (Folkerts, 1997; Neves et al., 1997). Many imperiled Smith River in North Carolina (Rosenberger, 2007; Roberts fishes found in the Conasauga River ( Cyprinella caerulea et al., 2009). The most recent management plan for P. rex (Jordan) , Noturus munitus Suttkus and Taylor , recognizes six populations: upper Roanoke River, middle Etheostoma ditrema Ramsey and Suttkus , Etheostoma Roanoke River, Pigg River, Smith River upstream of trisella Bailey and Richards and Percina antesella Philpott Reservoir, Smith River downstream of Philpott Williams and Etnier) are now isolated from other extant Reservoir, and Chowan Reservoir (Rosenberger, 2007). populations in the Mobile Basin by impoundments, with The populations in the Mayo and Smith rivers in North little opportunity for dispersal. Though the Conasauga Carolina had not been discovered yet (Roberts et al., River has been designated as critical habitat for 11 federal - 2009). ly listed species, and much of the headwaters drain Of the four populations of P. rex , the one in the upper National Forest, nonpoint-source pollution from agricul - Roanoke River has consistently been considered the ture and road construction continues to increase sedimen - healthiest (Jenkins and Burkhead, 1994). Visual surveys in tation and threaten the fauna (Burkhead et al., 1997; 2000 and 2001 found the population in the Chowan River Parmalee and Bogan, 1998). Subsequent urban sprawl drainage may be equally robust (Rosenberger and from Atlanta has further jeopardized the region; the Angermeier, 2003; Rosenberger, 2007). Many populations Conasauga and Etowah rivers contain a higher proportion are now affected by downstream impoundments, which of imperiled aquatic species than any similarly sized sys - alter riverine habitat and connectivity. Concerns about the tem in the southeastern United States (Burkhead et al., status of P. rex were first vocalized in the 1970s, as chem - 1997). ical spills and proposed dams threatened the species, espe - While there are no historical records indicating that cially the population in the upper Roanoke River (Jenkins either P. rex or P. jenkinsi ever occupied larger ranges, the and Burkhead, 1994). Though P. rex was listed as Federally occurrence of sympatric taxa with more widespread distri - Endangered in 1989 (U.S. Fish and Wildlife Service, 1989), butions suggests that their rarity may be relatively recent. critical habitat has not been designated. If these species have only recently become rare, conserva - Percina jenkinsi , the Conasauga logperch, is one of tion strategies should seek to halt their recent decline by the rarest fish in North America. It is known only from increasing available habitats to augment population size approximately 50 specimens taken from a 44-km reach of and prevent extinction (Hanski, 1998). However, if these the Conasauga River, a tributary of the Coosa River in the species have always been spatially rare or geographically Mobile Basin