Bernard R. Kuhajda

Diversity, Distribution, and Conservation Status of the Native Freshwater Fishes of the Southern United States

Abstract The Southeastern Fishes Council Technical Advisory Committee reviewed the diversity, distribution, and status of all native freshwater and diadromous fishes across 51 major drainage units of the southern United States. The southern United States supports more native fishes than any area of comparable size on the North American continent north of Mexico, but also has a high proportion of its fishes in need of conservation action. The review included 662 native freshwater and diadromous fishes and 24 marine fishes that are significant components of freshwater ecosystems. Of this total, 560 described, freshwater fish species are documented, and 49 undescribed species are included provisionally pending formal description. Described subspecies (86) are recognized within 43 species, 6 fishes have undescribed subspecies, and 9 others are recognized as complexes of undescribed taxa. Extinct, endangered, threatened, or vulnerable status is recognized for 28% (187 taxa) of southern freshwater and diadromou...

Guidelines for Propagation and Translocation for Freshwater Fish Conservation

Abstract Reestablishment of locally extinct populations and augmentation of declining populations are management activities used with increasing frequency in the conservation of imperiled fishes in the United States. Unfortunately, these options were not always carefully or appropriately used in past cases, partly owing to a lack of guidelines that address scientifically-based protocols for propagation, translocation, reintroduction, and augmentation (PTRA). PTRA programs are an important management tool for the recovery of imperiled fishes when undertaken with careful planning, including everything from determining that PTRA is necessary to incorporating knowledge of life history and genetics into the PTRA plan. In addition, PTRA programs must also assemble advisory groups, obtain funding and permitting, construct and maintain propagation facilities, and raise community awareness of the program. Because such diverse skills are needed, successful PTRA programs should prepare for long-term partnerships to ...

Drawn to the dark side: A molecular phylogeny of freshwater shrimps (Crustacea: Decapoda: Caridea: Atyidae) reveals frequent cave invasions and challenges current taxonomic hypotheses

Atyid freshwater shrimps are globally distributed and form an important part of freshwater ecosystems, particularly in the tropics and subtropics. Despite their widespread distribution and ecological importance, their phylogenetic relationships are largely unresolved. Here we present the first comprehensive molecular phylogeny of the Atyidae investigating the evolutionary relationships among 32 of the 42 genera using mitochondrial and nuclear markers. Our data indicate that the established classification of the Atyidae is in need of substantial taxonomic revision at all taxonomic levels. We suggest a new suprageneric systematization of atyids and discuss problematic issues at the generic level, particularly in the most speciose genus, Caridina. Molecular clock based divergence time estimates for atyids vary widely, but invariably support the assumption that atyids are an ancient freshwater lineage with an origin in the mid-Cretaceous at the very latest. Atyid distribution patterns are the result of instances of both long-distance dispersal and vicariance, depending largely on the reproductive mode of taxa. From an evolutionary perspective, the high frequency of independent origin of both a complete (landlocked) freshwater life cycle and a cave-dwelling mode of life is remarkable and unparalleled among crustaceans.

Phylogenetics of Scaphirhynchus Based on Mitochondrial DNA Sequences

Abstract Species delineation and taxonomy within the sturgeon genus Scaphirhynchus is controversial. This issue is made more complex by political issues regarding the Alabama sturgeon S. suttkusi and potential hybridization between sympatric shovelnose sturgeon S. platorynchus and pallid sturgeon S. albus. We investigated phylogenetic relationships among species of Scaphirhynchus based on nucleotide sequences for two mitochondrial loci, cytochrome b and the control region (D-loop). White sturgeon Acipenser transmontanus and green sturgeon A. medirostris were used as outgroups. Phylogenetic analyses did not recover monophyletic shovelnose or pallid sturgeon; however, some populations of pallid sturgeon were resolved as sister to the Alabama sturgeon, and one specimen of shovelnose sturgeon was consistently resolved as the sister to all other ingroup taxa. The hierarchical pattern of relationships produced by analysis of mitochondrial DNA is not consistent with that produced by morphological data. It is con...

Low genetic diversity and small long-term population sizes in the spring endemic watercress darter, Etheostoma nuchale

Species endemic to coldwater springs in the southeastern United States are some of the rarest and most imperiled in this region, yet little is known about their genetic composition and conservation needs. Here, microsatellite based levels of genetic diversity and estimates of effective population size (Ne) were compared between a narrow spring endemic fish, Etheostoma nuchale, and its widespread stream-dwelling relative, E. swaini. We applied several analytical methods to assess how demographic history is reflected in contemporary levels of genetic diversity for populations of E. nuchale. Phylogenetic analyses based on mitochondrial and nuclear DNA sequence data revealed a complex history among E. nuchale and E. swaini, but suggested ancient divergence and historic periods of isolation since colonization of spring habitats by E. nuchale. Populations of E. nuchale have levels of genetic diversity approximately one-half that of E. swaini, a result most likely due to founder effects and recent bottlenecks. Statistically significant Fst values (0.05−0.27) and STRUCTURE analyses implied high levels of differentiation among E. nuchale populations. Estimates of current Ne suggest relatively consistent levels across populations of E. nuchale, but one population may suffer from habitat degradation. We suggest that high levels of population structure and low levels of genetic diversity may be typical in other spring endemics inhabiting this region. Therefore, effective management planning for these unique species will require a detailed knowledge of the genetic and demographic history of each population.

Status of the federally endangered Alabama cavefish, Speoplatyrhinus poulsoni (Amblyopsidae), in Key Cave and surrounding caves, Alabama

Speoplatyrhinus poulsoni, the Alabama cavefish, is a federally endangered stygobitic fish that is restricted to Key Cave in northwestern Alabama. Due to the low abundance of this species and the continuous threats to the caves recharge area, we surveyed Key Cave from 1992 to 1997. Alabama cavefish were present in five different pools and had numbers comparable to previous surveys performed in the 1970s and 1980s. Three different size classes were observed, indicating recruitment is occurring. These data suggest that the population is relatively stable, but future monitoring is recommended. The Alabama cavefish is an endangered species and is extremely difficult to capture, therefore any marking program to accurately estimate the population size is unlikely. A single specimen of Typhlichthys subterraneus was captured in Key Cave. This falsifies the previous assumption that these two species are allopatric. Because of this discovery, we resurveyed seven caves in the area around Key Cave for additional populations of S. poulsoni. These caves had either known populations of T. subterraneus or unidentified cavefish. No additional populations of S. poulsoni were discovered, but further investigation is warranted. The Key Cave National Wildlife Refuge was established in the high recharge area of Key Cave to protect this habitat, yet threats to the groundwater continue from encroaching urbanization.

Habitat Use of the Watercress Darter (Etheostoma nuchale): An Endangered Fish in an Urban Landscape

Abstract The federally endangered watercress darter (Etheostoma nuchale) is restricted to only five springs within the greater Birmingham (AL) metropolitan area. Restricted range, subpopulation isolation and threats from the urban landscape are the major factors endangering the species. The preferred habitat of E. nuchale has been described as the deeper, slow-moving portions of spring pools with dense aquatic vegetation, but its habitat use patterns have not been carefully studied. Because the long-term survival of E. nuchale will likely depend on the protection and restoration of suitable habitat, more needs to be known about its preferred habitats. We studied habitat use patterns of E. nuchale and the geomorphologic and environmental conditions associated with these habitats in Seven Springs, a population recently discovered in 2003. Geomorphology and vegetation were surveyed throughout the spring pool and the spring run connecting it to the nearest tributary. Fish were surveyed via seining in eight distinct habitats. We found that E. nuchale can use a greater diversity of habitats than previously appreciated, including both shallow and non-vegetated habitats. While densities of adult fish were higher in vegetated habitats, fish of all ages and sexes were found in non-vegetated habitats where structural diversity is provided by detritus or gravel. Males were most abundant in mats of aquatic moss, while females showed no strong habitat associations other than avoiding habitats with no shelter. Juveniles were mainly associated with aquatic moss and pools with detritus. The best conditions for in-stream vegetation favored by E. nuchale were in the spring pool where the channel was broad, the current slow and shallow margins were extensive. Our findings suggest that habitat conservation plans that reduce storm water runoff and increase streambed and riparian stability, specifically in habitats downstream of springs that house E. nuchale, could promote aquatic vegetation growth and structural diversity, thus expanding the species usable habitat.

Life History of the Endangered Vermilion Darter (Etheostoma chermocki) Endemic to the Black Warrior River System, Alabama

ABSTRACT The endangered vermilion darter (Etheostoma chermocki) is endemic to the Black Warrior River system, Mobile Basin, Alabama. Collections of specimens obtained from October 1969 to January 2000 were evaluated to determine life history characteristics. Standard length was significantly correlated with body mass, gonad mass, and clutch size. Sex ratio (2:1) was in favor of females. Length frequency distribution and enumeration of otolith annuli revealed four different age classes (0 to 3). Vermilion darters matured at the end of the first year of life. Gonadosomatic index indicated reproduction occurred from March to June. Mean clutch size was 65 oocytes per female, and mean oocyte diameter was 1.14 mm. The vermilion darter is a generalist benthic invertivore, predominantly consuming larval chironomids, tipulids, and hydropsychids. Diet breadth was greatest during warmer months and least during colder months.

The influence of life-history strategy on genetic differentiation and lineage divergence in darters (Percidae: Etheostomatinae).

Recent studies determined that darters with specialized breeding strategies can exhibit deep lineage divergence over fine geographic scales without apparent physical barriers to gene flow. However, the extent to which intrinsic characteristics interact with extrinsic factors to influence population divergence and lineage diversification in darters is not well understood. This study employed comparative phylogeographic and population genetic methods to investigate the influence of life history on gene flow, dispersal ability, and lineage divergence in two sympatric sister darters with differing breeding strategies. Our results revealed highly disparate phylogeographic histories, patterns of genetic structure, and dispersal abilities between the two species suggesting that life history may contribute to lineage diversification in darters, especially by limiting dispersal among large river courses. Both species also showed striking differences in demographic history, indicating that extrinsic factors differentially affected each species during the Pleistocene. Collectively, our results indicate that intrinsic and extrinsic factors have influenced levels of gene flow among populations within both species examined. However, we suggest that life‐history strategy may play a more important role in lineage diversification in darters than previously appreciated, a finding that has potentially important implications for understanding diversification of the rich North American freshwater fish fauna.

Life History of the Warrior Darter (Etheostoma bellator) and Comparison with the Endangered Vermilion Darter (Etheostoma chermocki)

ABSTRACT The Warrior darter (Etheostoma bellator) is endemic to the Black Warrior River drainage (Mobile Basin) above the Fall Line in Alabama. Etheostoma bellator is a species complex, with the nominal form common and widespread, and includes a population in Gurley Creek in the lower Locust Fork in Blount County and Jefferson County, Alabama. Based on morphology and genetics, this population of Warrior darters has been identified as a potential surrogate for the federally endangered vermilion darter (E. chermocki), which is restricted to Turkey Creek, which is adjacent to Gurley Creek. Fresh collections of Warrior darters from November 2004 to June 2006 and museum collections were evaluated to determine life history characteristics. Standard length was significantly correlated with body mass and gonad mass. Males were larger than females, and the sex ratio (2:1) was in favor of females. Length frequency distribution and enumeration of otolith annuli revealed four age classes (0+ to 3+). Warrior darters matured at the end of the first year of life. Gonadosomatic index indicated reproduction occurred from March to June. Mean clutch size was 71 oocytes per female. The Warrior darter is an opportunistic benthic invertivore, predominantly consuming larval chironomids, tipulids, baetid mayflies, and glossosomatid and hydropsychid caddisflies. Diet breadth was greatest during warmer months and least during colder months. Based on current information, the Warrior darter appears to be the ideal surrogate for the endangered vermilion darter because both species share similar life history characteristics.