Black Bass Diversity: Multidisciplinary Science for Conservation

<em>Abstract</em>.—Bartram’s Bass (an as yet unnamed species similar to Redeye Bass <em>Micropterus coosae</em>) is endemic to the Savannah drainage of South Carolina and Georgia. Hybridization between this native species and introduced Alabama Bass <em>M. henshalli </em>is widespread in the upper portions of the drainage. Recent studies have documented a precipitous decline in genetically pure Bartram’s Bass in Savannah drainage reservoirs and a corresponding increase in fish of hybrid origin. We surveyed tributary populations associated with these reservoirs and with the Savannah River main stem in 2004 and 2010. Results indicate an increased occurrence of hybrids in Bartram’s Bass native stream habitats over time. We also document the new occurrence of a second nonnative species, Smallmouth Bass <em>M. dolomieu</em>. Both Smallmouth Bass and their hybrids with Bartram’s Bass were collected from shoals in the Savannah River near the lower extent of the Bartram’s Bass range. Bartram’s Bass is a species of highest conservation concern in South Carolina, due to its limited native range and threats associated with hybridization. Conservation actions directed at this species, and its native stream habitats, will need to consider the establishment of nonnative species in the drainage and their potential to impact tributary populations over time.

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>.—Reports of testicular oocytes (intersex) in fish are increasing worldwide. Intersex is often associated with estrogens in treated wastewater effluents, but few studies have explored other potentially explanatory factors. Our recent survey of intersex Largemouth Bass <em>Micropterus salmoides</em> in 11 impoundments across Georgia, USA found high incidence (>80%) of intersex fish in some impoundments but none in others. To explore factors associated with intersex in the impoundments, which did not receive wastewater, we examined potential predictor variables that varied among the levels of individual fish, impoundment, or landscape in a binomial mixed-model regression approach. Our model indicated effects of fish length, catch per unit effort (an index of fish density), and impoundment, which was the strongest effect. The probability of intersex was highest in smaller fish from impoundments with the highest catch rates. The underlying mechanism(s) for the impoundment effect remain unclear, but we hypothesize that estrogens excreted by high densities of fish and cyanobacteria may influence intersex. Additional studies are needed to understand the long-term population implications of intersex and the role of other biological and environmental factors, particularly at the impoundment level, in development of the intersex condition.

Black Bass Diversity: Multidisciplinary Science for Conservation

<em>Abstract</em>.—We reviewed the published and gray literature associated with Neosho Smallmouth Bass <em>Micropterus dolomieu velox</em> and the genetically distinct Ouachita lineage. Substantial interstream variation appears to occur among these populations, particularly related to age. The Neosho subspecies is more abundant, grows faster, and lives longer than the genetically distinct Ouachita lineage. Recruitment is highly variable among streams for both populations and appears to be related to some undescribed aspects of hydrology but also likely reflect bias due to sampling gear. Information on annual and seasonal trends is lacking for the Neosho subspecies and the Ouachita lineages, particularly as related to the spawning period. Conservation efforts for these lineages might benefit from agencies partnering to achieve goals that extend beyond a particular agency’s responsibilities and state boundaries. Recognition of spatial and temporal considerations, combined with a better understanding of the population dynamics as related to abundance, growth, mortality and reproduction, would benefit the creation of more effective conservation and management strategies for genetically distinct populations of Smallmouth Bass <em>M. dolomieu</em>.

Black Bass Diversity: Multidisciplinary Science for Conservation

<em>Abstract</em>.—The Guadalupe Bass <em>Micropterus treculii</em> is a central Texas endemic black bass species occurring only in streams and rivers draining the Edwards Plateau ecoregion. It is designated the state fish of Texas and provides a popular sport fishery. In addition to being a popular sport fish, it is listed as a species of special concern due to habitat degradation and hybridization with Smallmouth Bass <em>M. dolomieu</em>. Past socioeconomic surveys of Texas black bass anglers have focused primarily on reservoir fisheries while little is known about fishing patterns, economic impact, and preferences of river and stream anglers. A Web-based open-access survey was used to determine fishing characteristics, assess attitudes and quantify the economic impact of anglers fishing rivers and streams in a 24-county region of Texas from August 20, 2011 to December 20, 2012, with a focus on anglers who specifically fished for Guadalupe Bass. A total of 700 respondents participated in the survey. More than half of respondents were paddlers targeting black bass, and 42% specifically fished for Guadalupe Bass on their trips. An additional 34% of anglers listed black bass species, which included Guadalupe Bass as their preferred species. Similar to previous surveys of Texas river and stream anglers, access was identified as the largest impediment to the future maintenance and improvement of river and stream fishing. Based on 563 surveys used in the economic impact analysis, using IMPLAN (Impact Analysis for Planning) Professional version 2 (Minnesota IMPLAN Group, Minneapolis), an estimated US$74,182,080 in direct angler expenditures was spent on fishing trips to the study region, resulting in a total economic impact (including indirect and induced impacts) of $71,552,492 and 776 full-time jobs. These findings indicate the economic value of river and stream angling to the Texas economy.