Black Bass Species Research Articles

Alabama Bass Alter Reservoir Black Bass Species Assemblages When Introduced Outside Their Native Range

AbstractBlack bass Micropterus spp. stocked outside of their native range have often been implicated in declines of native fishes, but impacts of these stockings on native congeners have been examined less commonly and almost never in reservoirs. Relative abundance and creel data were obtained from seven reservoirs (632–13,156 ha) in four southeastern states where Alabama Bass M. henshalli had been illegally stocked. Genetics data for black bass were collected in nine more reservoirs in five southeastern states where similar introductions occurred. In each case, Alabama Bass introduction was swiftly followed by sweeping changes in the black bass composition. Largemouth Bass M. salmoides relative abundance declined by 42–77% after Alabama Bass introduction in four of five reservoirs, but total black bass relative abundance was unchanged in three of them, indicating that Alabama Bass essentially replaced Largemouth Bass. Alabama Bass or their hybrids dominated the black bass genetic sample in five of nine reservoirs, and pure specimens of non‐Alabama Bass species composed <50% of the sample in six of nine reservoirs. Smallmouth Bass M. dolomieu were virtually extirpated via hybridization with Alabama Bass in two of the study reservoirs, and genetically pure fish were rare in several others. These changes occurred over relatively short time intervals, often within 10 years after detection of Alabama Bass, stressing the need for continual vigilance via routine monitoring and a proactive public relations campaign to discourage and limit new introductions. The leading edge of the Alabama Bass invasion now encompasses several notable Smallmouth Bass fisheries in North Carolina and is on the border of numerous others in Tennessee, Virginia, and beyond. The spread of nonnative black bass, such as the Alabama Bass highlighted in this article, constitutes one of the greatest threats to conserving native black bass fisheries.

Failure of Phenotypic Markers to Accurately Identify Black Bass Species and Associated Hybrids in the Mobile River Basin, Alabama

AbstractHybridization among the black basses Micropterus spp. occurs due to weak postzygotic reproductive barriers and anthropogenic factors, such as habitat alteration. Introduction of previously allopatric species can also result in hybrid swarms and, in some cases, extirpation of native species. Introgressive hybridization is a major conservation concern for the more range‐restricted black basses, which underscores the need for accurate identification of hybrids that often have cryptic phenotypes. To that end, we collected 1,723 fish from four river systems in the Mobile River basin, Alabama, to compare phenotypic identification in the field based on morphology with genotype determined from single‐nucleotide polymorphism analysis using diagnostic markers for black basses. Results indicated that phenotypic identification among these cryptic hybrids was only 11% accurate. Only 4% of the fish collected were identified as hybrids in the field, whereas genotype analysis classified 22% of the fish as hybrids. The majority of those misidentified in the field were hybrids between Alabama Bass M. henshalli and Redeye Bass M. coosae or between those species and another black bass species. Hybrid individuals composed 5–38% of the total number of fish collected from the four river systems, but 28–68% were misidentified in each river system. These results underscore the need for genetic tools to augment classic field surveys of the black basses, as cryptic hybridization may lead to errant management decisions based on inaccurate species distribution assessments.

A Case of Mistaken Identity: Genetic and Morphological Evidence for the Presence of Redeye Bass in the Verde River, Arizona

Abstract 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 whether one of the black bass (Genus Micropterus) species historically introduced to the Verde River was Redeye Bass and whether they persist in the system. We extracted DNA from fin clips of five individuals for phylogenetic analysis of the nicotinamide adenine dinucleotide + hydrogen (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.

Habitat Associations of Three Black Bass Species in a Reservoir System

AbstractThe habitat associations of three species of black bass Micropterus spp. were examined in six habitat types (i.e., sediment, gravel, rock, riprap, brush, and aquatic plants) along a cascade of 10 reservoirs in the Tennessee River. We tested whether habitat selection differed among the three species and whether species’ co‐occurrence depended on habitat type. We found that some species occurred in some habitats in proportion to habitat availability (some at higher frequencies and some at frequencies lower than availability) and that juveniles and adults exhibited similar occurrence patterns. Our habitat selection results largely corroborate previous descriptions of black bass habitat associations and generally track preference for lithic habitats, as reported in native streams. We expected the different black bass species to show negative co‐occurrence to avoid competitive interactions. Nevertheless, we found that with few exceptions, adults co‐occurred in habitats mostly as expected by chance and juveniles co‐occurred more often than was expected by chance. Our findings imply that environmental filtering, rather than competitive interactions that dominate in natural environments, may be the dominant mechanism shaping black bass assemblages in reservoirs of the Tennessee River. The observed patterns of habitat selection and co‐occurrence further suggest that the conservation and management of black bass assemblages in reservoirs can be supported through habitat management activities. Protecting and enhancing the remaining lithic habitat in the reservoirs as well as recovering habitat that is blanketed by sediment could provide desirable environments for all black bass species.

Variation in Black Bass Angler Characteristics by Stream Size and Accessibility in Oklahoma’s Ozark Highland Streams

AbstractFishing in streams and rivers is a popular outdoor recreation activity in eastern Oklahoma, where most anglers target black bass (Micropterus) species. Since the early 1990s, when the last assessment of black bass fishing in the region was conducted, broadscale factors such as harvesting behavior, state fishery regulations, and bass population dynamics have changed. In 2018, we conducted creel and fish tagging surveys in three tributaries of Lake Tenkiller (Caney Creek, Baron Fork, and Illinois River) that differed in size and accessibility to provide current estimates of catch, harvest, and effort directed toward black bass. We then related these estimates to angler socioeconomic characteristics. The amount of angler effort was concomitant with stream size and accessibility, being greatest in the largest stream with the most access (Illinois River). However, catch rates were highest in the medium‐sized stream (Baron Fork). Harvest rates and exploitation were near zero in all systems. Anglers fishing Caney Creek, the smallest and least accessible stream, were nearly all local, coming from zip codes ~42 km away, with low median household incomes compared to anglers at the other streams who came from a broader array of more distant zip codes and had higher median household incomes. Anglers fishing the smallest stream were also more interested in harvesting fish and having higher creel limits than anglers at the other two systems. In the Oklahoma Ozark Highlands, stream size and accessibility appear to be a significant factor in angler demographics, potentially necessitating different management strategies.

Genetic Evidence of Introduced Redeye Bass and Alabama Bass and Hybridization with Native Micropterus spp. in Town Creek, Alabama, USA

AbstractThe black basses Micropterus spp. are among the most important game fishes in the United States. Translocation by both anglers and state agencies for increased angling opportunity has led to widespread hybridization between native and nonnative species. The use of species‐diagnostic single‐nucleotide polymorphism (SNP) markers for black basses has allowed for rapid assessment of species identification and hybridization in rivers and streams. Here, we report genetic evidence for the presence of Redeye Bass M. coosae and Alabama Bass M. henshalli outside of their native range and their hybridization with native species of black bass in Town Creek, a tributary of the Tennessee River. To determine which black bass species were present in the creek, four sites were sampled using both angling and backpack electrofishing. Sampled DNA from fin clips was analyzed using a diagnostic SNP panel. Genetic results confirmed that Redeye Bass and Alabama Bass were present as nonnative congeners in the creek. Interestingly, no pure individual Smallmouth Bass M. dolomieu or Spotted Bass M. punctulatus were found, although both species are native to the stream. Phenotypic identification followed by genotypic classification revealed that 62% of the fish collected for this study were misidentified in the field, with 100% of those being hybrids, indicating the importance of genetic assessment in conjunction with classic morphometrics for the management of black basses. Further studies are needed to determine whether seasonality plays a role in species presence and abundance and whether population profiles identified here are observed more broadly within the Tennessee River system.

A conservation-oriented SNP panel for Smallmouth Bass (Micropterus dolomieu), with emphasis on Interior Highlands lineages

The Smallmouth Bass (Micropterus dolomieu; SMB) is a widely distributed black bass species, but the southwestern edge of the species range within the Interior Highlands contains some of the most divergent ecotypes. The Neosho subspecies (M. d. velox) inhabits tributaries of the Arkansas River within the Ozark Mountains and a second lineage is reported from drainages of the Ouachita Mountains. We sought to develop a single nucleotide polymorphism (SNP) panel to (1) diagnose hybridization with sympatric Spotted Bass (Micropterus punctulatus; SPB) and non-native Northern SMB (M. d. dolomieu) stocked in the region, and (2) delineate population structure within the ranges of the Neosho and Ouachita SMB lineages. We obtained 76 individual SMB samples from across their range but concentrated within the Interior Highlands (n = 50). We also included 3 SPB to allow for hybrid detection and 3 Shoal Bass (Micropterus cataractae) as an outgroup. Phylogenetic trees constructed with the generated SNP data corroborated the existence of at least three major lineages of SMB (Northern, Neosho, and Ouachita), each containing varying degrees of differentiation among major drainages. Simulation analyses revealed that chosen SNPs had high power (> 0.9) to assign SMB × SPB hybrid categories and similarly high power (> 0.8) for Northern SMB × Interior Highlands SMB hybrids. Clustering methods delineated major inter-basin population structure within the native ranges of Neosho and Ouachita SMB with chosen SNPs. Anticipated uses of the resulting 192-loci SNP panel include conservation planning, fisheries management assessments, and ecological investigations of the Neosho and Ouachita SMB lineages.

Black Bass Growth Patterns in Relation to Hydrology in the Arkansas River, Arkansas

AbstractHydrology has been documented as affecting the recruitment of sport fishes. However, the potential cumulative effects of river hydrology on fish growth have not been intensively studied. In 2004, 2005, and 2010, annual growth increments were measured for Largemouth Bass Micropterus salmoides and Spotted Bass M. punctulatus populations from throughout the Arkansas portion of the Arkansas River. During three consecutive years (2007–2009), the lower Arkansas River experienced long durations of high water. Mean annual flows exceeded the 42‐year average by 52%, with summer flows averaging 107% above normal and 29% of the days annually exceeding 2,830 m3/s. Using age‐1–6 cohorts, we compared Largemouth Bass (n = 2,155) and Spotted Bass (n = 833) growth increments across hydrologic conditions occurring during the growth years experienced by these fish. Two‐way ANOVAs using back‐calculated age and growth year warm‐season hydrology (classified as high, average, or low flow based on quartiles from historical April–September hydrographs) as main effects suggested significant hydrologic effects on the growth of both black bass species. A significant interaction between back‐calculated age and growth year April–September hydrology for both black basses further suggested that flow affected growth differently across ages, with decreased annual growth increments detected for the age‐1–3 cohorts. Decreased annual growth occurring during 2007–2009 also was consistent with a 0.5‐year increase in the age at which Largemouth Bass attained 381 mm TL (i.e., the minimum length required for legal harvest) in 2010. Similarly, Spotted Bass required an extra 0.9 year to attain 304 mm TL (i.e., a common minimum length limit). Results suggested that the typically beneficial effects of high‐flow years on black bass populations in large‐river–floodplain systems may be dampened or non‐existent in more highly regulated, impounded river systems, such as the modern‐day Arkansas River.

Age and growth of stocked juvenile Shoal Bass in a tailwater: Environmental variation and accuracy of daily age estimates.

Otolith microanalysis is often used to assess population age structure and growth of fishes during their early stages. Shoal Bass Micropterus cataractae is a recently described species of conservation concern and little is known regarding factors affecting their recruitment. In 2004, Georgia Department of Natural Resources (GADNR) and the US National Park Service (NPS) stocked Shoal Bass marked with oxytetracycline (OTC) in the Chattahoochee River near Atlanta, Georgia in an effort to restore this population, creating known-age fish to examine the effect of environment on daily age accuracy. We obtained samples of stocked juvenile (<150 mm) Shoal Bass from standard monitoring that occurred approximately 30–60 days after stocking in the Chattahoochee River to 1) validate daily rings for estimating age, hatch dates, and growth rates for stocked age-0 Shoal Bass, and 2) evaluate the effect of habitat (location) on age bias. Shoal Bass otoliths were examined for OTC marks and daily rings were counted in reference to OTC marks to assess age estimation accuracy. Age estimation accuracy ranged from -2 to -25 days and was influenced by the environment where Shoal Bass were captured, with greater inaccuracy in colder water temperatures. Fish collected from locations with colder temperatures displayed closer spacing of daily rings, potentially leading to greater underestimation of age. Growth rates of stocked Shoal Bass, corrected for age estimation error, ranged from 0.5 mm/day to 0.8 mm/day. This study demonstrates the effect of environmental variability on age inaccuracy and subsequent interpretation of results. Incorporating methods to assess age estimation accuracy is needed to understand interspecific differences in recruitment among black bass species in the variety of natural and human-modified environments they inhabit.

Factors influencing methylmercury contamination of black bass from California reservoirs

Understanding how mercury (Hg) accumulates in the aquatic food web requires information on the factors driving methylmercury (MeHg) contamination. This paper employs data on MeHg in muscle tissue of three black bass species (Largemouth Bass, Spotted Bass, and Smallmouth Bass) sampled from 21 reservoirs in California. During a two-year period, reservoirs were sampled for total Hg in sediment, total Hg and MeHg in water, chlorophyll a, organic carbon, sulfate, dissolved oxygen, pH, conductivity, and temperature. These data, combined with land-use statistics and reservoir morphometry, were used to investigate relationships to size-normalized black bass MeHg concentrations. Significant correlations to black bass MeHg were observed for total Hg in sediment, total Hg and MeHg in surface water, and forested area. A multivariate statistical model predicted Largemouth Bass MeHg as a function of total Hg in sediment, MeHg in surface water, specific conductivity, total Hg in soils, and forested area. Comparison to historical reservoir sediment data suggested there has been no significant decline in sediment total Hg at five northern California reservoirs during the past 20 years. Overall, total Hg in sediment was indicated as the most influential factor associated with black bass MeHg contamination. The results of this study improve understanding of how MeHg varies in California reservoirs and the factors that correlate with fish MeHg contamination.

An evaluation of the current extent and potential spread of Black Bass invasions in South Africa

Black Bass, a collective name for members of the centrarchid genus Micropterus, are native to North America, but have been introduced globally to enhance recreational angling. This study assessed the distribution of Micropterus salmoides, M. dolomieu and M. punctulatus in South Africa using both formal (survey-based) and informal (tournament data and social media) information sources. Analysis of the distribution data showed habitat bias between the data sources. Survey data from formal information sources were dominated by locality records in riverine environments while those derived from informal information sources focused more on lacustrine habitats. Presence data were used to develop niche models to identify suitable areas for their establishment. The predicted distribution range of M. salmoides revealed a broad suitability over most of South Africa, however, the Cape Fold Ecoregion and all coastal regions were most suitable for the establishment for both M. dolomieu and M. punctulatus. Flow accumulation and precipitation of coldest quarter were the most important environmental variables associated with the presence of all Black Bass species in South Africa. In addition, anthropogenic disturbance such as agricultural activities were associated with the presence of both Smallmouth Bass and Spotted Bass. An extensive area-based invasion debt was observed for all Micropterus spp. The potential for further spread of Black Bass in South Africa is of ecological concern because of their impact on native biota.

Precision and Accuracy of Age Estimates Obtained from Anal Fin Spines, Dorsal Fin Spines, and Sagittal Otoliths for Known-Age Largemouth Bass

Sagittal otoliths are the preferred aging structure for Micropterus spp. (black basses) in North America because of the accurate and precise results produced. Typically, fisheries managers are hesitant to use lethal aging techniques (e.g., otoliths) to age rare species, trophy-size fish, or when sampling in small impoundments where populations are small. Therefore, we sought to evaluate the precision and accuracy of 2 non-lethal aging structures (i.e., anal fin spines, dorsal fin spines) in comparison to that of sagittal otoliths from known-age Micropterus salmoides (Largemouth Bass; n = 87) collected from the Ocmulgee Public Fishing Area, GA. Sagittal otoliths exhibited the highest concordance with true ages of all structures evaluated (coefficient of variation = 1.2; percent agreement = 91.9). Similarly, the low coefficient of variation (0.0) and high between-reader agreement (100%) indicate that age estimates obtained from sagittal otoliths were the most precise. Relatively high agreement between readers for anal fin spines (84%) and dorsal fin spines (81%) suggested the structures were relatively precise. However, age estimates from anal fin spines and dorsal fin spines exhibited low concordance with true ages. Although use of sagittal otoliths is a lethal technique, this method will likely remain the standard for aging Largemouth Bass and other similar black bass species.

Shoal bass life history and threats: a synthesis of current knowledge of a Micropterus species

The shoal bass (Micropterus cataractae) is a black bass species native to the Apalachicola-Chattahoochee-Flint Basin of the southeastern U.S. Damming in the basin has created extensive habitat loss; consequently, shoal bass have been extirpated from several areas of their native range. Early shoal bass research focused on age and growth, spawning habits, and distribution. The formal recognition of the species in 1999 increased interest in research and restoration. Recent research has described critical habitat, movements, and systematic information about shoal bass. As researchers continue to investigate the life history of the species, several threats have become apparent including habitat modification, interactions with non-native black basses, and the effects of angling. Currently, management needs include basic population assessments and investigation of factors causing population declines. Despite increased interest in the species, the outlook for the long-term conservation of the shoal bass is uncertain.

Trends and Synchrony in Black Bass and Crappie Recruitment in Missouri Reservoirs

AbstractLargemouth Bass Micropterus salmoides, Spotted Bass M. punctulatus, White Crappie Pomoxis annularis, and Black Crappie P. nigromaculatus are popular components of many large reservoir sport fisheries, and a better understanding of these populations and their dynamics would improve our management capabilities. We used long‐term datasets (13–37 years) collected from 15 Missouri reservoirs to assess temporal trends and synchrony in sport fish recruitment by using catch per unit effort of age‐1 (CPUE1) black bass Micropterus spp. during spring electrofishing (N/h) and CPUE1 of crappies Pomoxis spp. during fall trap‐netting (N/net‐night) as our index of recruitment. Although CPUE1 exhibited high interannual variation within a reservoir, time series analysis revealed only two significant trends for each of the black bass species, with all trends indicating increasing recruitment. White Crappie CPUE1 showed abrupt declines in all four reservoirs in the Osage River basin, with these declines occurring in different years in each reservoir. White Crappie CPUE1 in one northern reservoir and Black Crappie CPUE1 in all reservoirs appeared to be increasing over time. Within a species, some regional synchrony in CPUE1 occurred for Largemouth Bass, White Crappie, and Black Crappie but not for Spotted Bass. However, synchrony within a species was not universal and in some cases did not exist even among arms within large reservoirs. With few exceptions, there was little evidence for synchronous recruitment among species; those that occurred were among congeners. The lack of synchrony among black bass and crappie recruitment suggests that management practices designed to improve recruitment of one species may not enhance the recruitment of another species.

Hearing sensitivity in two black bass species using the auditory brainstem response approach

Recently, several bioacoustic studies have focused on the red eye bass (Micropterus coosae). One of these studies documented sound production, while the other played back sounds produced by prey items in order to determine their attractiveness to M. coosae. Surprisingly, the hearing ability of fishes in the genus Micropterus has received very little attention. The need for audiograms describing hearing in Micropterus is apparent. This study utilized the auditory brainstem response (ABR) approach to determine hearing sensitivity in terms of both sound pressure level (SPL) and particle acceleration in two black bass species, the red eye bass (M. coosae) and the Alabama bass (M. henshalli). Audiograms produced in this study expressed in both SPL and particle acceleration showed a positive relationship between hearing threshold and frequency. Micropterus coosae was most sensitive to frequencies that overlap with the peak frequencies of their vocalizations, and the vocalizations of a prey species, Cyprinella trichroistia. Bass hearing sensitivities at lower frequencies, measured in terms of particle acceleration, were similar to several sciaenid species.

Smallmouth Bass and Largemouth Bass Predation on Juvenile Chinook Salmon and Other Salmonids in the Lake Washington Basin

AbstractWe assessed the impact of predation by smallmouth bass Micropterus dolomieu and largemouth bass M. salmoides on juveniles of federally listed Chinook salmon Oncorhynchus tshawytscha and other anadromous salmonid populations in the Lake Washington system. Bass were collected with boat electrofishing equipment in the south end of Lake Washington (February–June) and the Lake Washington Ship Canal (LWSC; April–July), a narrow waterway that smolts must migrate through to reach the marine environment. Genetic analysis was used to identify ingested salmonids to obtain a more precise species‐specific consumption estimate. Overall, we examined the stomachs of 783 smallmouth bass and 310 largemouth bass greater than 100 mm fork length (FL). Rates of predation on salmonids in the south end of Lake Washington were generally low for both black bass species. In the LWSC, juvenile salmonids made up a substantial part of bass diets; consumption of salmonids was lower for largemouth bass than for smallmouth bass. Smallmouth bass predation on juvenile salmonids was greatest in June, when salmonids made up approximately 50% of their diet. In the LWSC, overall black bass consumption of salmonids was approximately 36,000 (bioenergetics model) to 46,000 (meal turnover consumption model) juveniles, of which about one‐third was juvenile Chinook salmon, one‐third was coho salmon O. kisutch, and one‐third was sockeye salmon O. nerka. We estimated that about 2,460,000 juvenile Chinook salmon (hatchery and wild sources combined) were produced in the Lake Washington basin in 1999; thus, the mortality estimates in the LWSC range from 0.5% (bioenergetics) to 0.6% (meal turnover). Black bass prey mostly on subyearlings of each salmonid species. The vulnerability of subyearlings to predation can be attributed to their relatively small size; their tendency to migrate when water temperatures exceed 15°C, coinciding with greater black bass activity; and their use of nearshore areas, where overlap with black bass is greatest. We conclude that under current conditions, predation by smallmouth bass and largemouth bass has a minor impact on Chinook salmon and other salmonid populations in the Lake Washington system.

Distribution and Abundance of Black Bass in Skiatook Lake, Oklahoma, after Introduction of Smallmouth Bass and a Liberalized Harvest Regulation on Spotted Bass

AbstractWe conducted a 3‐year study to examine the trends in abundance and distribution of three sympatric black bass species (Micropterus) in an Oklahoma reservoir after implementation of a differential harvest regulation to reduce the abundance of spotted bass M. punctulatus and after stocking nonnative smallmouth bass M. dolomieu. Largemouth bass M. salmoides were stocked in Skiatook Lake, Oklahoma, immediately after its creation in 1984 to supplement the existing population in the watershed. Nonnative smallmouth bass were stocked in 1990, and their abundance and distribution have increased ever since. Native spotted bass, which have less fishery value than the other two black bass species, increased fivefold in abundance in 1994, became the predominant black bass species by at least 1996, and appeared to displace largemouth bass from many habitats. From boat‐mounted electrofishing sampling conducted in April and May 1997–1999, we found that spotted bass abundance (proportion and catch per hour) had decreased while smallmouth bass abundance and distribution within the reservoir steadily increased. Largemouth bass abundance did not change among years. Throughout our study period, spotted bass was always the most abundant black bass species where differences in abundance were found. Our results suggest that the continually expanding smallmouth bass population is displacing spotted bass from many of their formerly used habitats, much like spotted bass had displaced largemouth bass by 1996.

Phylogenetics of freshwater black basses (Centrarchidae: Micropterus) inferred from restriction endonuclease analysis of mitochondrial DNA.

Geographic isolation and habitat specialization has aided in the evolution and genetic integrity of the micropterid bass species of North America. Members of the genus Micropterus form a close natural unit with little morphologic and meristic variation. Our goals were to measure the genetic characteristics of and distances between six black bass species by using mitochondrial DNA analysis. Mitochondrial DNA restriction fragment length polymorphisms were examined in Guadalupe bass (M. treculi), largemouth bass (M. salmoides), shoal bass (M. cataractae), smallmouth bass (M. dolomieu), spotted bass (M. punctulatus), and Suwannee bass (M. notius), using 15 restriction endonucleases. The bluegill (Lepomis macrochirus) was used as an outgroup. The phylogeny inferred from Dollo parsimony cladistic analysis concurred with published results from allozyme analyses, yet it was inconsistent with published meristic analyses. Genetic distances between species ranged from 0.0659 to 0.2145, with the largemouth and Suwannee basses showing the greatest divergence from the other black basses. The Guadalupe, smallmouth, and spotted basses were most diverged from the bluegill. The black basses diverged over a broad time frame, with estimated black bass speciation occurring during late Miocene-early Pliocene (3.30-10.73 MYA).

Modification of an index of biotic integrity and development of reference condition expectations or dunal, palustrine wetland fish communities along the southern shore of Lake Michigan

I modified and calibrated an index of biotic integrity (IBI) to assess wetland quality of dunal, palustrine wetlands along the southern shore of Lake Michigan. Fish communities were sampled using a combination of electrofishing and seining techniques to collect a representative sample. A combination of 50 historical and recent sites were sampled from northeast. Illinois and northwest Indiana to develop reference expectations for dunal wetlands less than 35 ha surface area. I examined 36 attributes of wetland fish communities to derive a dunal, palustrine IBI. Several metrics from the original IBI were retained including: total number of species, number of sensitive species, and percent tolerant species. Trophic composition characters included the percentage of omnivores and insectivores. Fish condition was evaluated using the catch-per-unit of effort and the percentage of deformities, eroded fins, lesions, and tumours (DELT). Several metrics were modified from the original IBI to better reflect water resource quality in dunal wetlands. The number of darter species was replaced by a combination of the ecologically similar number of darter and madtom species; number of sunfish species was modified to the number of centrarchid species, which included the black bass species; number of sucker species was replaced by the number of minnow species since few sucker species were anticipated in dunal wetlands; and I substituted percent carnivores with percent pioneer species. Pioneer species reflect wetland stability and water permanence. Hybrids were not important constituents of wetland communities and did not show a relationship with wetland degradation, so I substituted the percentage of lake-obligate species to reflect species that were dominant in lentic waters.

Modification of an index of biotic integrity and development of reference condition expectations or dunal, palustrine wetland fish communities along the southern shore of Lake Michigan

Abstract I modified and calibrated an index of biotic integrity (IBI) to assess wetland quality of dunal, palustrine wetlands along the southern shore of Lake Michigan. Fish communities were sampled using a combination of electrofishing and seining techniques to collect a representative sample. A combination of 50 historical and recent sites were sampled from northeast Illinois and northwest Indiana to develop reference expectations for dunal wetlands less than 35 ha surface area. I examined 36 attributes of wetland fish communities to derive a dunal, palustrine IBI. Several metrics from the original IBI were retained including: total number of species, number of sensitive species, and percent tolerant species. Trophic composition characters included the percentage of omnivores and insectivores. Fish condition was evaluated using the catch-per-unit of effort and the percentage of deformities, eroded fins, lesions, and tumours (DELT). Several metrics were modified from the original IBI to better reflect water resource quality in dunal wetlands. The number of darter species was replaced by a combination of the ecologically similar number of darter and madtom species; number of sunfish species was modified to the number of centrarchid species, which included the black bass species; number of sucker species was replaced by the number of minnow species since few sucker species were anticipated in dunal wetlands; and I substituted percent carnivores with percent pioneer species. Pioneer species reflect wetland stability and water permanence. Hybrids were not important constituents of wetland communities and did not show a relationship with wetland degradation, so I substituted the percentage of lake-obligate species to reflect species that were dominant in lentic waters.