Micropterus Research Articles

AFS Roots: James Alexander Henshall, the Apostle of the Black Bass

AFS Roots: James Alexander Henshall, the Apostle of the Black Bass

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.

Genetic Structure of Smallmouth Bass in the Lake Michigan and Upper Mississippi River Drainages Relates to Habitat, Distance, and Drainage Boundaries

AbstractAnalysis of genetic connectivity helps to define stock boundaries and provides information on interpopulation dynamics, such as migration and spawning site fidelity. We used 16 microsatellite loci to describe the genetic population structure of 1,215 Smallmouth Bass Micropterus dolomieu from 32 sites throughout the upper Mississippi River and Lake Michigan watersheds. We found that Smallmouth Bass populations formed two genetically distinct units separated by the Mississippi River–Lake Michigan drainage boundary. Smallmouth Bass from the Lake Michigan drainage could be parsimoniously grouped into two or six genetically distinct units that largely corresponded with either river or lake habitats, while fish from the Mississippi River drainage grouped into two, six, or nine genetic units that were mostly associated with watershed boundaries. In the Lake Michigan and Mississippi River drainages, relative migration was limited between lake and river sites, suggesting that gene flow between neighboring sites with different habitat attributes can be low. Our research provides a higher‐resolution assessment of Smallmouth Bass genetic structure in a core portion of the species’ range and provides strong evidence that Smallmouth Bass populations are structured at small spatial scales that are potentially associated with habitat type. These results demonstrate the importance of evaluating genetic structure at small spatial scales and adopting management strategies that preserve genetic diversity of black bass populations at both the watershed level and the habitat level.

Carbon:nitrogen ratio as a proxy for tissue nonpolar lipid content and condition in black sea bass Centropristis striata along the Middle Atlantic Bight

Spatial and temporal variability in fish tissue lipid content may reflect resource availability, reproductive or maturity state, or environmental suitability. Here, we analyzed nonpolar (storage) lipid and morphometric condition indices of black sea bass (Centropristis striata) collected from coastal waters of the Northwest Atlantic Ocean from New Jersey to North Carolina, USA. We hypothesized that the elemental ratio of carbon to nitrogen (C:N) within C. striata white muscle and liver tissue would be a robust proxy for nonpolar lipid content (NPLC) and that NPLC would predictably covary with traditional condition indices. Further, we analyzed our NPLC tissue indices to determine how regional and biological patterns in muscle and liver NPLC aligned with traditional condition indices. Our results indicated that muscle tissue NPLC was low compared to liver tissue, and regression analysis revealed strong positive relationships between C:N and NPLC for both tissues (muscle—best fit was linear; liver—best fit was asymptotic nonlinear). Correlations of muscle and liver NPLC with other condition indices were index and region dependent (e.g., a reproductive index was positively correlated with muscle NPLC, but negatively correlated with liver NPLC). Tissue NPLC and standard condition indices differed significantly as a function of region, sex, and fish length, although the patterns were not consistent across the different indices. Our results support the use of muscle and liver C:N values to estimate tissue-specific C. striata NPLC. Further, our results indicate that NPLC indices provide additional insight into C. striata physiological condition and could assist studies examining habitat suitability across large spatial or temporal scales.

On Improved Care of Black Bass During Live‐Release Competitive Angling Events – Recent Innovations and Associated Research Needs

On Improved Care of Black Bass During Live‐Release Competitive Angling Events – Recent Innovations and Associated Research Needs

Food preferences of Pike Perch, Sander lucioperca (Linnaeus, 1758) in Morocco

Sander luciopercahasbeen introduced in Morocco since 1939. This noble fish has shown a good ability to acclimatize to Moroccan conditions and has developed well [1]. The present study examines diet composition and predator-prey relationships that are dependent on size and weight between sander and its preys during the period October 2018-April 2019. Stomach contents of 287 specimens, whose size varies between 17 and 72 cm, from Al-Massira dam, wereanalyzed. The results showed that Sander feeding is composed of six categories of prey, the most important species was the Blue gill (Perch) with an occurrence index equal to 14.9%, the occurrence indices for other preys were respectively : Pike perch (8.01%), Tilapia (5.57%), Roach (0.69%), Black bass (0.69%) and Common carp (0.69%). It has been found that the total length of the preys increases with that of the Pike perch. Thus, the Pike perch is able to ingest preys of big weight and size. We also revealed that cannibalism was high, indicating a lack of forage fish in this lake.

Black Basses as Skeletal Preparation Materials in Environmental Education Program

Black Basses as Skeletal Preparation Materials in Environmental Education Program

Quantifying contributions to tournament catches among resident, stocked and hybrid black basses (Micropterus spp.)

AbstractMillions of Florida bass, Micropterus floridanus Lesueur, are stocked annually into populations of largemouth bass, Micropterus salmoides Lacepède, to increase trophy fish abundance. However, little effort has related the role that resultant hybrids make to angler catches. Largemouth bass were sampled from an important recreational fishery subject to extensive Florida bass stocking to address the hypothesis that anglers capture Florida bass, largemouth bass and hybrids at rates equivalent to their overall abundance in the population. Fin clips obtained from tournament angling events (n = 348) and boat‐mounted electrofishing sampling (n = 219) were screened at 38 species‐diagnostic markers and individuals were assigned to genealogical classes using Bayesian clustering algorithms. No significant differences were identified between angler and electrofishing catches providing evidence that hybridised individuals stemming from a long‐term stocking programme may constitute an important contribution to tournament angling catch.

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.

The Importance of Live‐Well Transport in the Physiological Disturbance Experienced by Smallmouth Bass in Tournaments on Large Water Bodies

AbstractCompetitive fishing has become an important element of recreational fisheries for black bass Micropterus spp. in North America. The vast majority of competitive events involve a “live‐release” format, where fish are held in a boat's live well after being angled and are then released following the weigh‐in. We examined the frequency and importance of physical impacts between Smallmouth Bass Micropterus dolomieu and the walls of the live well when tournaments are held on large water bodies. Using an experimental live well that included a video recorder, we determined the number of collisions between Smallmouth Bass and the walls of the live well when a 5.6‐m boat was driven on Lake Ontario. During these experiments, 10 of 28 Smallmouth Bass lost equilibrium and became inverted. Live‐well transport also resulted in elevations of intracellular enzymes in blood plasma that were used as indicators of cell damage. The results of these experiments indicate that physical impacts with the walls of the live well may be an important factor contributing to the physiological disturbance experienced by Smallmouth Bass in tournaments on large water bodies. Our results also show that this disturbance can be reduced by simply padding the live well. These findings have important implications for fisheries managers, as well as the competitive angling community.

The Effects of Regulated Area Location and Size on the Effectiveness of a Catch‐and‐Release Season for a Riverine Black Bass

AbstractCatch‐and‐release areas are an extension of the concept of aquatic protected areas, which implement protective measures at a broad spatial scale in an attempt to increase conservation efforts. Also, catch‐and‐release areas are commonly used to regulate sport fisheries, particularly in specific areas during the spawning season. However, the size and location of catch‐and‐release areas are rarely evaluated in terms of their effects on the success of these regulations in protecting these species. Empirical exploitation data were used with an age‐structured model to explore changes in population biomass and size structure of Shoal Bass Micropterus cataractae in the Flint River, Georgia, with simulated changes in the location and size of catch‐and‐release areas during the spawning season. Annual exploitation of Shoal Bass with no catch‐and‐release area was 0.257 and was reduced 0–21% when a catch‐and‐release regulation was simulated in a specific reach. Models predicted significant increases in population biomass and size structure using catch‐and‐release reaches as short as 33 km, but this was contingent upon which specific reaches were designated as catch and release. As area size increased, population biomass and size structure of the population increased, but the rate of increase depended upon the specific areas incorporated. Designation of the entire reach would decrease annual exploitation by 50%, but large portions of the study area could be designated as catch and release with little changes in population biomass or size structure due to low harvest rates. This study illuminated the importance of spatial patterns of harvest in determining effectiveness of catch‐and‐release areas, which should be an important consideration in the placement of such aquatic protected areas.

Proposed Standard Weight (Ws) Equation and Standard Length Categories for Shoal Bass

AbstractStandard weight (Ws) equations have been proposed for a variety of fishes, including many of the black basses Micropterus spp. We developed Ws equations for Shoal Bass M. cataractae by using the traditional regression‐line‐percentile (RLP) technique and the relatively new empirical‐percentile (EmP) method. Length and weight data for 9,058 Shoal Bass from 15 populations were used in this analysis. These fish were collected from 1978 to 2017 by various agency and university personnel from most of the known populations across the species’ range in Alabama, Florida, and Georgia. The resulting Ws equations were log10W = 3.243·log10L − 5.490 for the RLP technique and log10W = 1.225·log10L + 0.415·(log10L)2 – 3.052 for the quadratic EmP technique, where W is weight (g) and L is TL (mm). Unlike the quadratic EmP equation, the RLP equation exhibited a slight length‐related bias on each end of the length spectrum, so we recommend the EmP technique as the preferred equation for this species. To assess fish population size structure, we also propose minimum lengths for five standard TL categories of 18, 28, 35, 43, and 51 cm for stock, quality, preferred, memorable, and trophy sizes, respectively. Development of a Ws equation and standard TL categories will aid biologists in evaluating and monitoring Shoal Bass populations as part of continuing conservation efforts.

Species-diagnostic SNP markers for the black basses (Micropterus spp.): a new tool for black bass conservation and management

Black basses (genus Micropterus) are apex predators in North American streams, rivers, and lakes and important game fishes. Translocation and introductions for angling, accompanied by intrinsically weak genetic barriers, have led to widespread introgressive hybridization and genetic swamping. Species-diagnostic (fixed allele) SNP markers have been utilized successfully in salmonids to monitor hybridization and genetic integrity. Here, we developed similar resources for black basses through initial genotyping-by-sequencing, followed by validation in additional samples using two panels of 64 SNPs. Results from > 1300 genotyped bass indicated that the developed panels robustly and clearly delineate fifteen species and their hybrids among black basses. The panels represent a flexible, rapid turnaround (~ 1 day), and cost-effective tool that should augment ongoing efforts toward black bass conservation and management.

Ecology and timing of black bass spawning in Lake Ontario and the St. Lawrence River: Potential interactions with the angling season

The timing of spawning for largemouth bass and smallmouth bass in Lake Ontario and the St. Lawrence River was examined over a 3-year period. Temperatures were warmer in the preferred spawning habitat of largemouth bass, and the majority of nests had offspring that had reached the swim-up stage at the opening of the bass angling season in 2 of the 3 years examined. In contrast, the proportion of smallmouth bass nests that had reached the swim-up stage when the bass angling season opened ranged from 4 to 13% during these years. Using models created from nest observations and temperature data, we provide estimates of the additional time required to allow higher percentages (20%, 50% and 80%) of smallmouth bass nests to reach the swim-up stage. Invasive round goby, which are an important nest predator, were more abundant in the spawning habitat preferred by smallmouth bass. A simulated angling experiment showed that round gobies invaded about half of the nests when the guarding male was briefly angled and released. In view of these results, it may be important to re-evaluate the dates for the closed season in order to maintain the quality of the bass fisheries in Lake Ontario and the St. Lawrence River.

A Statewide Evaluation of Florida Bass Genetic Introgression in Tennessee

AbstractThe Largemouth Bass (LMB) Micropterus salmoides is one of the most popular freshwater sport fish in the United States, and managers in southeastern states have stocked its subspecies, the Florida Bass (FLB) M. salmoides floridanus, outside of the subspecies’ natural range to increase the size structure of existing LMB populations. In Tennessee, fisheries for LMB are concentrated in reservoirs of the Cumberland and Tennessee River systems; however, FLB stockings have to date been restricted to two reservoirs of the Tennessee River and have varied significantly in extent and duration. We quantified levels of genetic admixture between FLB and LMB by using 38 species‐diagnostic single‐nucleotide polymorphisms for 979 fish sampled from 14 reservoirs within the Cumberland and Tennessee River systems. We tested for differences in genetic admixture across river systems and evaluated the relative importance of fish stockings in explaining observed levels of genetic admixture. Levels of admixture and associated variation were higher in Tennessee River reservoirs (average percentage of FLB alleles: range = 6.3–30.4%) than in Cumberland River reservoirs (range = 5.7–13.4%), but admixture was not solely related to stocking rates. The highest levels of FLB introgression were detected in Chickamauga Reservoir, the most extensively stocked reservoir in the state. Linear models identified fish stocked as a significant overall predictor of admixture, but we also observed stocked and unstocked reservoirs with similar levels of admixture, suggesting that factors other than stocking influence population genetics. Our statewide assessment of reservoir‐level patterns of hybridization among black bass was performed prior to the recent expansion of FLB stocking efforts in Tennessee and thus represents a baseline for evaluation of future stocking.

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.

Using species-diagnostic SNPs to detail the distribution and dynamics of hybridized black bass populations in southern Africa

The widespread introduction of Largemouth Bass (Micropterus salmoides) and Florida Bass (M. floridanus) to establish sport fisheries represents a significant conservation concern given their role as apex predators and their ability to alter community diversity and species abundance. In regions like southern Africa, which has both high levels of aquatic endemism and imperilment, limiting the spread of invasive predators is a primary goal of current alien species legislation. Here, we applied two panels of species-diagnostic SNPs for a total of 60 markers to map the distribution of Largemouth Bass, Florida Bass, and their hybrids in 13 southern African water bodies. Using Bayesian clustering algorithms we documented the introgression of Florida Bass alleles across a broad geographic range, from the Cape Floristic region of South Africa to Mozambique. Several populations previously considered pure Largemouth Bass based on mitochondrial DNA sequences were found to consist exclusively of hybrids. Samples collected from Lake Chicamba, which was initially established with pure Largemouth Bass, are now almost exclusively comprised of Florida Bass alleles (89.3 % Florida Bass). The estimated hybrid class of sampled fish (e.g., F1 hybrid, pure Largemouth Bass, pure Florida Bass) showed that with few exceptions, populations were dominated by a single hybrid class. The present work provides enhanced resolution of the distribution and dynamics of Florida Bass, Largemouth Bass, and their hybrids in southern Africa.

Mercury and selenium levels, and Se:Hg molar ratios in freshwater fish from South Louisiana

Ample historical evidence has demonstrated the neurotoxicity of organic Hg. However, several studies have suggested that Se effectively sequesters MeHg. The affinity of Hg is up to ≈106 times higher for Se molecules than for comparable sulfur molecules, most of which are components of brain enzymes. The neurotoxicity of MeHg is associated with its binding to Se and the resultant interference with selenoenzymes (Ralston & Raymond, Global Advances in Selenium Research from Theory to Application, 2016). Therefore, having ample Se reserves is an effective way to mitigate MeHg’s toxicity. When the molar ratios of Se to Hg in fish exceed 1.0, ingestion of the fish is unlikely to deplete Se reserves. The goal of this study was to determine the Hg and Se levels, and the Se:Hg molar ratios in freshwater fish from south Louisiana and the implications of those ratios with respect to fish consumption and Hg advisories. Five waterbodies were surveyed (University lake, Calcasieu lake, Toledo Bend, the Atchafalaya River and Henderson Lake). The sampled species included black drum (Pogonias cromis), catfish sp., largemouth bass (Micropterus salmoides) and bluegill (Eupomotis macrochirus). All fish were assayed for total Hg and Se. The average Hg concentration was 0.001 µmol g−1 (0.21 ppm), and all concentrations were below the 1 ppm US FDA action level (from 3.1 × 10–5 to 0.003 µmol g−1). Se concentrations exceeded Hg concentrations in most cases. The average Se concentration was 0.003 µmol g−1 (0.27 ppm), all concentrations were around or less than 1.0 ppm (from 3.7 × 10–4 to 0.017 µmol g−1). Hence, the Se:Hg molar ratios were >1 in all fish except largemouth bass from Henderson Lake. In general, Se was detected in sufficient amounts to sequester Hg, but consumption of largemouth bass from Henderson Lake would pose no risk only if anglers followed the posted Hg advisory. For advisory purposes, perhaps, both Hg and Se levels and Se:Hg molar ratios should be considered. In general, the results indicated that risk assessment will require consideration of both the fish species and body of water, because both can influence Se and Hg concentrations and Se:Hg molar ratios.