A case of mistaken identity: Genetic and morphological evidence for the presence of Redeye Bass in the Verde River, Arizona

We report genetic and morphological evidence for the presence of Redeye Bass Micropterus coosae, in the Verde River of Arizona, previously thought to be Smallmouth Bass Micropterus dolomieu. We performed meristic measurements on 15 individuals sampled from the Upper Verde River Wildlife Area, Yavapai County, Arizona. Meristic data for lateral line scales, scales above lateral line, and scales below lateral line were all consistent with Redeye Bass and not Smallmouth Bass. We analyzed mitochondrial and nuclear genetic data to determine if one of the black bass (Genus Micropterus) species historically introduced to the Verde River was Redeye Bass and that they persist in the system. We extracted DNA from fin clips of five individuals for phylogenetic analysis of the NADH dehydrogenase subunit 2 (ND2) mitochondrial gene and for analysis of nuclear DNA using a diagnostic Single Nucleotide Polymorphism (SNP) panel. Results of the ND2 genetic sequencing and phylogenetic analysis indicated that these fish likely originated from native Redeye Bass stock from the Coosa River system of Alabama, Georgia, and Tennessee. Similarly, nuclear SNP data from the five individuals collected from the Verde River aligned with Redeye Bass reference genotypes based on STRUCTURE analysis. These results support the hypothesis that at least one of the introductions of black bass in Arizona’s Verde River founded a previously unrecognized population of Redeye Bass. Further work is needed to determine the extent of the Redeye Bass presence in Arizona, whether Smallmouth Bass are also present in the Verde River system, and if hybridization of Redeye Bass and other black basses is occurring.

Effect of Discharge on Hatching and Growth of Age-0 Black Bass in Two Southeastern U.S. Rivers

We examined the influence of variable discharge on hatching and age-0 growth for fluvial specialist and habitat generalist species of black bass Micropterus spp. in two southeastern U.S. rivers, the Flint River, Georgia (unregulated), and the Tallapoosa River, Alabama (regulated by several hydropower dams). Between 2008 and 2010, we collected 285 Largemouth Bass M. salmoides (generalist) and 254 Shoal Bass M. cataractae (specialist) from two reaches of the Flint River. In 2010–2011, we collected 309 Alabama Bass M. henshalli (generalist) and 216 Redeye Bass M. coosae (specialist) from two regulated reaches and one unregulated reach of the Tallapoosa River. Successful hatching of black bass in both rivers generally occurred from late March to early June when water levels were low and stable. Hatching distributions of all black bass were generally unimodal with little evidence of spawning disruption, except for Alabama Bass in the most-regulated reach of the Tallapoosa River, which appeared to be disrupted by large discharge events. Mean growth of both species in the Flint River varied from 0.64 to 0.82 mm/d across reaches and years; Shoal Bass generally grew faster than Largemouth Bass in all reach–year combinations. Largemouth Bass growth was inversely correlated to discharge variation in one reach, but Shoal Bass growth was not correlated to discharge variation in either reach. Alabama Bass and Redeye Bass growth rates in the Tallapoosa River were similar to rates observed for congeners in the Flint River; Alabama Bass grew faster than Redeye Bass. Growth of both species was inversely related to discharge variation in five of six reach–species combinations; the only exception was for Redeye Bass in the less-regulated reach. Results from this study suggest that variable discharge has less influence on successful reproduction of black bass than was reported for other fishes, but growth may be more affected by discharges resulting from anthropogenic sources than those associated with the natural regime.

Black Bass Diversity: Multidisciplinary Science for Conservation

<em>Abstract</em>.—Rivers and streams of the southern United States contain more than 1,800 aquatic species, 500 of which are regionally endemic. At present, 34% of the fish species and 90% of the mussel species in peril nationwide are found in these systems. Declines in these imperiled species are due to many factors, including hydrologic alteration, degraded water quality, loss of instream and watershed connectivity, physical habitat degradation, and the negative effects of nonindigenous species (e.g., predation on, competition with, and hybridization with native forms). In addition, this situation is exacerbated through human population growth, competing water demands, land-use changes, and other interrelated issues. If unchecked, these issues will likely continue to contribute to the imperilment and loss of native species in the region. Of the nine described species and subspecies of black bass, six are endemic to the southern United States: Guadalupe Bass <em>Micropterus treculii</em>, Shoal Bass <em>M. cataractae</em>, Redeye Bass <em>M. coosae</em>, Florida Bass <em>M. floridanus</em>, Alabama Bass <em>M. henshalli</em>, and Suwannee Bass <em>M. notius</em>. In addition, undescribed species and subspecies also exist and all are in need of conservation measures to prevent them from becoming imperiled. In an effort to focus and coordinate actions to support the long-term persistence of endemic black bass populations, local, state, and federal agencies, universities, nongovernmental organizations, and corporations from across the region joined with the National Fish and Wildlife Foundation to form the Native Black Bass Initiative (NBBI). The NBBI provides regional conservation strategies, objectives, and targets to restore and preserve functional processes in those watersheds that support natural habitat conditions and sustainable populations of endemic black bass and other native fishes of the region. Initial actions implemented through the NBBI focus on addressing the conservation needs of Guadalupe Bass in streams of the Edwards Plateau ecoregion of Texas, Redeye Bass in the Savannah River watershed of Georgia and South Carolina, and Shoal Bass populations in the Apalachicola River watershed of Alabama, Florida, and Georgia.

Black Bass Diversity: Multidisciplinary Science for Conservation

<em>Abstract</em>.—Little is known about the movement and habitat use of Alabama Bass <em>Micropterus henshalli</em> and Redeye Bass <em>M. coosae</em>, especially in response to altered flow regimes resulting from hydropeaking operations. Therefore, 22 Alabama Bass and 20 Redeye Bass were implanted with radio tags and tracked every 3 weeks for 37 weeks from December 2010 to September 2011 to describe seasonal patterns in movement and habitat use in the Tallapoosa River, Alabama, below R. L. Harris Dam. Additionally, fish of each species were tracked weekly every 2 h over the course of 10 h to assess the effects of altered flows on movement and habitat use by the two species during different periods of the hydrograph (base, rising, peak, and falling flows). Movement of both species was strongly associated with season, with the highest movement in the spring. Total home range (95%) and core areas (50%) of both species were similar, but Redeye Bass total home range was inversely related to fish size. Alabama Bass were typically found in fine-sediment substrates and increasingly used more woody debris for cover from winter to summer, whereas Redeye Bass were typically found in rocky substrate and only used woody debris in summer. Neither Alabama Bass nor Redeye Bass daily movement appeared to be affected by the altered flow; however, Alabama Bass were found closer to shore in vegetated or woody debris habitat during high flows in spring and summer. In contrast, Redeye Bass showed little lateral movement in the river or change in habitat use in response to higher flows in most seasons but, similar to Alabama Bass, were found in shoreline vegetated habitats more often during high flows in spring. These shifts in habitat during different flows should be further investigated to evaluate possible life-history strategies.

Black Bass Diversity: Multidisciplinary Science for Conservation

<em>Abstract</em>.—Shoal basses are a cryptic clade composed of <em>Micropterus </em>spp. restricted to the Apalachicola River system and three southeastern Atlantic slope river drainages in the southeastern United States. This reciprocally monophyletic clade includes the Shoal Bass <em>M. cataractae </em>(endemic to the Apalachicola River system), the Chattahoochee Bass <em>M. chattahoochae</em>, and two undescribed forms from the Altamaha, Ogeechee, and Savannah River drainages. Members of the shoal bass clade can be distinguished from all other species of <em>Micropterus </em>basses using 20 diagnostic characters (characteristic attributes) found in mitochondrial DNA (NADH dehydrogenase subunit 2) gene sequences. Each member of the clade additionally possesses unique characteristic attributes, which along with morphological and meristic characters can be used to diagnose this cryptic biodiversity. Biologists and managers have previously regarded the shoal basses in the Chattahoochee, Savannah, Altamaha and Ogeechee River systems as belonging to a single taxon synonymous with the Redeye Bass <em>M. coosae</em>, which is endemic to the Mobile River drainage. With these and previous analyses (including description of the Shoal Bass), we now recognize that what was once considered a single taxon actually comprises seven species, each of which is endemic to a single southeastern drainage. Recognizing and documenting the actual diversity of <em>Micropterus </em>spp. provides important information for managers who may wish to avoid stocking or translocations that could compromise the genetic integrity of native bass populations. Introductions of nonnative basses, including Alabama Bass <em>M. henshalli</em>, Spotted Bass <em>M. punctulatus</em>, and Smallmouth Bass <em>M. dolomieu </em>currently threaten the integrity of native shoal bass species in streams of the Chattahoochee, Altamaha, Ogeechee, and Savannah River systems.

Diversity within the Redeye Bass, Micropterus coosae (Perciformes: Centrarchidae) species group, with descriptions of four new species

The Redeye Bass, Micropterus coosae, was described from the Mobile River basin, Chattahoochee, and Savannah rivers in Alabama and Georgia, USA, by Hubbs and Bailey (1940). At that time the authors recognized significant variation in the Black Warrior River population, and noted that with further study this form may be recognized as a separate taxon. An examination of variation in morphology and mitochondrial DNA supported this observation, and highlighted additional species-level variation, resulting in descriptions of a total of four new species: Micropterus cahabae, new sp., restricted to the Cahaba River system; Micropterus tallapoosae, new sp., restricted to the Tallapoosa River system; Micropterus warriorensis, new sp., from the Black Warrior River system; and Micropterus chattahoochae, new sp., from the Chattahoochee River system. Micropterus coosae is restricted to the Coosa River system. The new species differ from each other and from M. coosae by a combination of pigmentation and scale count characteristics, development of the tooth patch, and divergence within the ND2 gene. While two of these species are relatively common in upland streams within their ranges, M. warriorensis, M. cahabae and M. chattahoochae are uncommon and may warrant protection.