Walleye
Genetic Technician 2018
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An analysis of habitat use and suitability of Abrams Creek for reintroduction of the Blotchside Logperch (Percina burtoni) and genetic strategies for a successful reintroduction
Genetic Technician 2019 - present
Logperch species, including the Blotchside Logperch, have a unique feeding strategy that is not duplicated by any other darter species. They ‘flip’ rocks with their conical-shaped noses, and, in the act of disturbing substrate, they dislodge insects on which they feed. This feeding process loosens sediment and may improve habitat suitability for other aquatic species. It may, however, also increase the vulnerability of this species to excess sedimentation and substrate embeddedness, as has been observed for other, closely related logperch species in studies that identify this critical habitat need (i.e. clean substrate; Rosenberger and Angermeier 2003; Roberts and Rosenberger 2008). Further, logperch are also important hosts for endangered mussel species, including the Dromedary Pearlymussel Dromus dromas and the Fanshell Cyprogenia stegaria (Freshwater Mussel Host Database 2017). These factors make them a key player in restoring Abrams Creek to its former level of diversity and ecosystem function. The purpose of this proposed project is to provide guidance for the ongoing reintroduction of the Blotchside Logperch into Abrams Creek. Although within the species’ former range, isolation due to the Chilhowee Resevoir from source populations make it highly improbable Blotchside would independently recolonize Abrams Creek. Further, changes in habitat configurations since the 1950s may have altered the suitability of this system for logperch, highlighting the need for an assessment to insure enough adequate habitat is in Abrams Creek to sustain a logperch population and make ongoing reintroduction efforts worthwhile. Finally, information will inform how many genetically robust individuals will be required to reestablish a viable, self-sustaining population. We propose two primary components to our project, one to address demographic and genetic concerns, the other to address habitat suitability. Sampling will take place in known populations of Blotchside Logperch using backpack electrofishing methods. At least 15 individuals for each population will be collected. Length (mm) and a clip from the lower caudal fin will be taken prior to releasing individuals back to the site. Fin clips will be collected with sterile equipment and archived to maintain DNA integrity. With these clips, we will perform genotyping by sequencing (GBS) and single nucleotide polymorphisms (SNP’s) to assess population genomics as described by Elshire et al. (2011). Using filtered SNPs, we will calculate multiple genomic attributes, including population structure, analysis of molecular variance, observed heterozygosity, allelic richness, mean pairwise fixation index within a site, and genetic effective population size. These metrics will provide genetic baselines from which we can: 1) evaluate our success in capturing and maintaining the breadth of Blotchside Logperch genetic variation in newly reintroduced populations within Abrams Creek, 2) establish minimum numbers of individuals needed to capture the genetic variability of the population(s), and 3) inform selection of source-stock.
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Funding Source: Tennessee Aquarium Conservation Institute, Arkansas State University, Superb, Arkansas Center for Biodiversity Collections, Tennessee Cooperative Fishery Research Unit, Great Smoky Mountains National Park
Phylogeographic analyses suggest cryptic diversity within the Bluntnose Darter, (Etheostoma chlorosoma)
Undergraduate Project
Previous morphological studies of the Bluntnose Darter (Etheostoma chlorosoma) revealed little variation among populations across the Gulf Coastal Plain. Although some western populations (e.g. Colorado River, Texas) showed significant divergence from other populations, there was little support for taxonomic recognition of these populations. In this study, we sampled E. chlorosoma from multiple river drainages across the southeastern United States to examine patterns of phylogeographic structuring among populations throughout its distribution range. Phylogeographic reconstructions and species tree estimations were conducted using the mtDNA cytochrome b gene and six nuclear DNA loci of sampled individuals. Preliminary results from phylogenetic analyses of nuclear DNA markers revealed a pattern of divergence between two clades of E. chlorosoma; a “western” group including all populations in and west of the Sabine River, and an “eastern” group including populations east of the Sabine River. Preliminary analyses of mtDNA revealed a deep phylogeographic break (TMRCA approx. 8 mya) among the eastern and western haplogroups of E. chlorosoma. However, the mtDNA-based patterns suggest multiple instances of mtDNA introgression among eastern and western haplogroups since their initial divergence. Despite this pattern of mtDNA introgression, the deep divergence among eastern and western clades of E. chlorosoma suggests previously unrecognized cryptic diversity within the species. Increased sampling across the distribution of E. chlorosoma will need to be incorporated into this framework in order to fully understand the taxonomic status of these unique clades.
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Funding Source: Arkansas State University and Arkansas Center for Biodiversity Collections
Projects
Population genetic assessment of the endangered Cumberland Darter, (Etheostoma susanae)
Master's Project 2019 - present
The Cumberland Darter (Etheostoma susanae) is an endangered species of freshwater fish endemic to the tributaries of the Cumberland River above the Cumberland Falls in Kentucky and Tennessee. Once recognized as a subspecies of Johnny Dater (E. nigrum), E. susanae was elevated to species level based on morphological and mtDNA variation. Habitat degradation and modification is a primary concern for the species with its preference for slow-flow streams. Fragmented populations increase the risk of disrupting historic gene flow between tributaries which could potentially result in genetically distinct populations. Fin clips were obtained from eight localities across the range of E. susanae for a total of 188 samples. An additional 86 samples were collected for comparative purposes from four localities for E. nigrum, two of which were thought to be potential hybridization zones for E. susanae and E. nigrum in the Cumberland and Upper Kentucky River drainages. Samples combined for both species totaled to 274 individuals obtained from 11 sample sites. To better understand the evolutionary history, patterns of genetic structure, and the potential for hybridization between E. susanae and E. nigrum, we analyzed data from both mitochondrial DNA (mtDNA)and microsatellite DNA loci. Microsatellites and mtDNA revealed no evidence of recent or ongoing hybridization or introgression between E. susanae and E. nigrum. Microsatellite data further revealed moderate to high levels of genetic structuring among several populations of E. susanae. These results will later be combined with ongoing RADSeq data analyses, providing a comprehensive genetic roadmap that will be useful for conservation and management strategies involving E. susanae.
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Funding Source: Tennessee Aquarium Conservation Institute, Arkansas State University, Superb, Arkansas Center for Biodiversity Collections
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An analysis of habitat use and suitability of Abrams Creek for reintroduction of the Blotchside Logperch (Percina burtoni) and genetic strategies for a successful reintroduction
Genetics Technician 2019 - present
Logperch species, including the Blotchside Logperch, have a unique feeding strategy that is not duplicated by any other darter species. They ‘flip’ rocks with their conical-shaped noses, and, in the act of disturbing substrate, they dislodge insects on which they feed. This feeding process loosens sediment and may improve habitat suitability for other aquatic species. It may, however, also increase the vulnerability of this species to excess sedimentation and substrate embeddedness, as has been observed for other, closely related logperch species in studies that identify this critical habitat need (i.e. clean substrate; Rosenberger and Angermeier 2003; Roberts and Rosenberger 2008). Further, logperch are also important hosts for endangered mussel species, including the Dromedary Pearlymussel Dromus dromas and the Fanshell Cyprogenia stegaria (Freshwater Mussel Host Database 2017). These factors make them a key player in restoring Abrams Creek to its former level of diversity and ecosystem function. The purpose of this proposed project is to provide guidance for the ongoing reintroduction of the Blotchside Logperch into Abrams Creek. Although within the species’ former range, isolation due to the Chilhowee Resevoir from source populations make it highly improbable Blotchside would independently recolonize Abrams Creek. Further, changes in habitat configurations since the 1950s may have altered the suitability of this system for logperch, highlighting the need for an assessment to insure enough adequate habitat is in Abrams Creek to sustain a logperch population and make ongoing reintroduction efforts worthwhile. Finally, information will inform how many genetically robust individuals will be required to reestablish a viable, self-sustaining population. We propose two primary components to our project, one to address demographic and genetic concerns, the other to address habitat suitability. Sampling will take place in known populations of Blotchside Logperch using backpack electrofishing methods. At least 15 individuals for each population will be collected. Length (mm) and a clip from the lower caudal fin will be taken prior to releasing individuals back to the site. Fin clips will be collected with sterile equipment and archived to maintain DNA integrity. With these clips, we will perform genotyping by sequencing (GBS) and single nucleotide polymorphisms (SNP’s) to assess population genomics as described by Elshire et al. (2011). Using filtered SNPs, we will calculate multiple genomic attributes, including population structure, analysis of molecular variance, observed heterozygosity, allelic richness, mean pairwise fixation index within a site, and genetic effective population size. These metrics will provide genetic baselines from which we can: 1) evaluate our success in capturing and maintaining the breadth of Blotchside Logperch genetic variation in newly reintroduced populations within Abrams Creek, 2) establish minimum numbers of individuals needed to capture the genetic variability of the population(s), and 3) inform selection of source-stock.
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Funding Source: Tennessee Aquarium Conservation Institute, Arkansas State University, Superb, Arkansas Center for Biodiversity Collections, Tennessee Cooperative Fishery Research Unit, Great Smoky Mountains National Park
Conservation genetic assessment of the endangered Yellowcheeck Darter, (Nothonotus moorei)
Genetics Technician 2018
The Yellowcheek Darter, Nothonotus moorei, is a riffle specialist found in the Little Red River drainage of Arkansas. Abundance of N. moorei at historically known localities was estimated to have declined by 85% from 1981 to 2004, which was attributed to episodes of drought, habitat alteration, and increased siltation. In conjunction with these factors and restricted distribution, N. moorei was listed as endangered by USFWS in the 2011. Previous genetic studies using allozymes and AFLPs revealed significant genetic structuring among the four main tributaries occupied by N. moorei (Archey, South, Middle, and Beech forks), with further concern of restricted gene flow due to Greers Ferry Reservoir. This study used mtDNA sequence data and 10 microsatellite loci to evaluate patterns of genetic structure and diversity among the four populations of N. moorei, with the goal understanding both historical and contemporary patterns of genetic diversity to better inform potential propagation and translocation efforts. Results from mtDNA suggested weak, but significant structuring among the four populations (Fst = 0.18, P < 0.01). Pairwise Fst comparisons, however, showed that Middle Fork differed from all populations, but no other population pair was significantly different. Microsatellite-based analyses indicated weak but significant structuring among the four populations (Fst = 0.09, P < 0.01), and all pairwise comparisons were significant. Bayesian cluster analysis of microsatellite data indicated three groups with strong individual assignments: South and Archey forks; Middle Fork; and Beech Fork. Taken together, patterns of mtDNA and microsatellite diversity suggest that populations of N. moorei were likely more connected historically, but have become contemporarily structured possibly due to reservoir fragmentation. Middle and Beech fork populations appear to be most distinct when compared to the other populations, and it is recommended that propagation or translocation programs treat them independently of one another and from Archey and South forks.
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Funding source: U.S. Fish & Wildlife, Arkansas State University, Superb, Arkansas Center for Biodiversity Collections
Assessment of Walleye in the Eleven Point River, Arkansas, following a six-year stocking gap
Genetics Technician 2018
The Eleven Point River contains a native population of Walleye that is genetically distinguishable from populations at northern latitudes. Supplemental stocking of non-native northern strain Walleye (Great Lakes region stock) occurred in the Arkansas portion of the Eleven Point River from 1986 to 2011. Previous analyses in 2002 indicated that 52% of Walleye sampled were non-native genetic strain (based on mitochondrial [mt] DNA haplotypes) and constituted approximately half of each year-class. This objective of this project was to assess the genetic composition of Walleye in the Arkansas portion of the Eleven Point River following a six-year cessation of stocking. During fall of 2017 and 2018, 216 Walleye were sampled and genotyped for eight microsatellite DNA loci and sequenced for the mtDNA control region. An additional 30 Walleye from Greers Ferry Lake were included in analyses, representing a hatchery source for non-native Walleye stocked in the Eleven Point River. Microsatellite-based assignment tests identified 85% of Walleye in the Arkansas portion of the Eleven Point River as native strain, 8% as non-native strain, and 7% as putative hybrids. Only 5% of Walleye carried the non-native mtDNA haplotype. These preliminary finding suggest a sharp decline in non-native Walleye strains from 2011 to 2017.
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Funding Source: Arkansas State University, Arkansas Center for Biodiversity Collections
Phylogeographic analyses suggest cryptic diversity within the Bluntnose Darter, (Etheostoma chlorosoma)
Undergraduate Project 2016 - 2018
Previous morphological studies of the Bluntnose Darter (Etheostoma chlorosoma) revealed little variation among populations across the Gulf Coastal Plain. Although some western populations (e.g. Colorado River, Texas) showed significant divergence from other populations, there was little support for taxonomic recognition of these populations. In this study, we sampled E. chlorosoma from multiple river drainages across the southeastern United States to examine patterns of phylogeographic structuring among populations throughout its distribution range. Phylogeographic reconstructions and species tree estimations were conducted using the mtDNA cytochrome b gene and six nuclear DNA loci of sampled individuals. Preliminary results from phylogenetic analyses of nuclear DNA markers revealed a pattern of divergence between two clades of E. chlorosoma; a “western” group including all populations in and west of the Sabine River, and an “eastern” group including populations east of the Sabine River. Preliminary analyses of mtDNA revealed a deep phylogeographic break (TMRCA approx. 8 mya) among the eastern and western haplogroups of E. chlorosoma. However, the mtDNA-based patterns suggest multiple instances of mtDNA introgression among eastern and western haplogroups since their initial divergence. Despite this pattern of mtDNA introgression, the deep divergence among eastern and western clades of E. chlorosoma suggests previously unrecognized cryptic diversity within the species. Increased sampling across the distribution of E. chlorosoma will need to be incorporated into this framework in order to fully understand the taxonomic status of these unique clades.
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Funding Source: Arkansas State University, Arkansas Center for Biodiversity Collections
Project Macroinvert: Bringing Aquatic Macroinvertebrate Collections Out of the Dark at Arkansas State University
Collections Preparator 2017 - 2019
The Arkansas State University Museum of Zoology (ASUMZ) Aquatic Macroinvertebrate collection at the Arkansas Center for Biodiversity Collections (ACBC) houses approximately 130,000 specimens (17,000 lots). The collection includes specimens from North and Central America and Australia, but most of the specimens were collected in Arkansas by George L. Harp and his students from the early 1970s to his retirement in 1999. Since then, the collection has been stored and not well curated. Project Macroinvert was initiated at the ACBC in fall of 2016, which involves restoration, digitization, and georeferencing of the collection by undergraduate and graduate students. Until recently, specimen data were stored in handwritten catalogs, making query and locality mapping cumbersome and time consuming. To date, approximately 95% of the collection has been digitally databased, with approximately 50% of the records having sufficient data for georeferencing. To highlight the utility of data unlocked by Project Macroinvert, we map and describe distributional data from ASUMZ specimens in the orders Odonata (Dragonflies and Damselflies) and Ephrmeroptera (Mayflies). We expect that digitization and georeferencing of small collections, such as the ASUMZ collection, will contribute vastly to our knowledge of species distributions and our ability to accurately characterize biodiversity at fine scales.
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Funding Source: Arkansas State University, Arkansas Center for Biodiversity Collections