AUTHORS: Caitlin Bloomer, University of Illinois Urbana-Champaign; Joel Corush, Illinois Natural History Survey; Mark Davis, Illinois Natural History Survey; Maxwell Hartman, Arkansas Game and Fish Commission
ABSTRACT: The Slenderwrist Burrowing Crayfish, Fallicambarus petilicarpus, is a short-range endemic restricted to the Ouachita River drainage in south-central Arkansas and northern Louisiana. U.S. Fish and Wildlife Service is currently evaluating this species for listing as threatened or endangered under the Endangered Species Act (ESA). Since 2021, teams of inter-agency biologists have been collecting data on this species to inform the listing decision. We used species distribution modeling to identify habitat associations and estimate the total available habitat within the known range of this species. We used Restriction-site associated DNA sequencing (RADseq) to establish effective population size and estimate genetic differentiation between populations. Here we will present an overview of our data collection and how our results support the listing of this species under the ESA. We will also highlight the major data gaps that still exist and how we plan to address them through future field studies.
AUTHORS: Patrick F. Allison Jr., University of Mississippi; Corey G. Dunn, U.S. Geological Survey, North Carolina Cooperative Fish & Wildlife Research Unit; North Carolina State University; Susan B. Adams, USDA Forest Service, Southern Research Station, Center for Bottomland Hardwoods Research; Jesse W. Breinholt, LGC RAPiD Genomics; Kenneth A. Sterling, USDA Forest Service; Devin M. Raburn, North Carolina Cooperative Fish & Wildlife Research Unit; North Carolina State University; Zanethia C. Barnett, USDA Forest Service, Southern Research Station, Center for Bottomland Hardwoods Research; Ryan C. Garrick, University of Mississippi
ABSTRACT: Recent advancements in morphological data collection and molecular phylogenetics have resulted in numerous updates to crayfish taxonomy. However, there are still problematic taxa among these decapods. The genus Hobbseus is one such group, as the morphological characters traditionally used for species identification can provide ambiguous diagnoses. Given that some Hobbseus species have been petitioned for listing under the Endangered Species Act, this uncertainty is particularly concerning, as it inhibits implementation of effective conservation strategies. We reassess the taxonomy of Hobbseus using an integrative approach to species delimitation that combines morphological and molecular data. We include four complementary datasets: 1) traditional morphometrics; 2) geometric morphometrics; 3) single-locus mitochondrial DNA sequences; and 4) multi-locus hybrid enrichment single copy nuclear DNA sequences. Here, we provide preliminary results from analyses of the DNA sequence datasets.
AUTHORS: ZAchary J. Loughman, West Liberty University; Parker Hildreth, Tennessee Wildlife Resource Agency; Jonathan D. Eisenhour, Office of Kentucky Nature Preserves; Eric Ng, West Liberty University, Kaleb Norris, West Liberty University; Kathryn Schulz, West Liberty University; Michael C. Compton, Office of Kentucky Nature Preserve.
ABSTRACT: Cambarus jezerinaci, the Spiny Scale Crayfish, is a small headwater species endemic to the central Appalachians of Kentucky, Tennessee, and Virginia. Recently C. jezerinaci was petitioned for federal listing, resulting in the need for a Species Status Assessment (SSA). With the exception of C. jezerinaci description, limited surveys have been completed for this taxa. Cambarus jezerinaci has an interesting distribution in Kentucky, with populations known to occur prior to survey efforts in the South Fork of the Kentucky River basin, as well as the Upper Cumberland watershed. In the summer of 2022, a weeklong survey effort procured new C. jezerinaci locations in the Middle Fork of the Kentucky River, as well as the Upper Cumberland. Genetic samples were taken on all animals captured and analyzed with 2 COI genes. Results of this work indicated that multiple lineages existed for C. jezerinaci in Kentucky that differ genetically from type populations, warranting more dedicated work. In the summer of 2024, in accordance with the Kentucky Crayfish Blitz as well as the WLU Crayfish Laboratory, 306 sites were sampled across the entirety of the Kentucky Fork basins, as well as the Upper Cumberland watersheds. Cambarus cf. jezerianci was procured from 28.2% of sites sampled. Genetic samples were acquired from all specimens and will be analyzed using RADSeq methods. Future work will focus on elucidating the conservation genetics and taxonomic standing of C. jezerinaci to support the completion of the SSA.
AUTHORS: Dusty Swedberg, Prairie Research Institute - Illinois Natural History Survey; Archis Grubh, Texas Parks and Wildlife Department; Christopher Taylor, Prairie Research Institute - Illinois Natural History Survey
ABSTRACT: Crayfishes are a diverse and ecologically important component in Texas's aquatic ecosystems. Timely information on distribution, abundance, habitat needs, and threats is needed to effectively manage this resource. Texas currently has ten crayfish species of greatest conservation need, five of which were the focus of our sampling: Procambarus brazoriensis, Procambarus nigrocinctus, Procambarus nechesae, Procambarus nueces, and Procambarus texanus. From 2022 to 2024, we sampled almost 100 sites targeting these species and have been able to collect each of the five species. Our collections and the associated habitat data have documented possible range reduction in Procambarus nueces and Procambarus texanus. While also documenting Procambarus nigrocinctus and Procambarus nechesae might be more common than initially perceived. Procambarus brazoriensis is documented as a highly seasonal crayfish with collections that only occur in early spring. With our collection data, we are able to draw conclusions on range and habitat data to better estimate the conservation status for these five crayfishes and other sympatric species that were collected through our efforts.
AUTHORS: Hannah Holbert, West Liberty University; Zackary Graham, West Liberty University; Zachary Loughman, West Liberty University
ABSTRACT: There is no standard for individual captive husbandry of Cambaridae crayfish species, despite captive propagation being an important factor in reintroduction efforts. The Big Sandy Crayfish (Cambarus callainus) and the Guyandotte River Crayfish (Cambarus veteranus) are recognized under the Endangered Species Act as Threatened and Endangered, respectively. Active propagation projects are underway for C. callainus, but standards are still being developed. In order to set a baseline protocol for these federally listed Cambarus species, a shelter preference study was conducted using the Big Water Crayfish (Cambarus robustus). C. robustus is a large-bodied, tertiary burrowing crayfish species native to the eastern coast of the United States and Ontario, Canada. C. robustus commonly occurs in lotic environments and prefers large slab boulders for shelter. Due to similar life history strategies and habitat preferences, this species serves as a potential surrogate for related species such as C. callainus. 31 individual crayfish took part in two trials each, where shelter choices included a natural rock shelter and a piece of clear acrylic, or a natural shelter and tinted acrylic. Trials were conducted for 24-hours, where shelter usage and behavior were monitored through video recordings. Our results suggest that C. robustus will use all shelter types, although natural shelters were occupied more frequently overall. Sex and size of the individuals had minimal or no influence on shelter use. Future research should continue to investigate optimal husbandry practices and rearing techniques for Cambarus species where propagation efforts are necessary.
AUTHORS: Calvin R. Rezac, Mississippi Museum of Natural Science, Mississippi Department of Wildlife, Fisheries, and Parks
ABSTRACT: In 2020, a genetic and morphological evaluation of the Rusty Gravedigger (Lacunicambarus miltus) by Glon et al. supported the elevation of two new species, the Banded Mudbug (L. freudensteini) and the Lonesome Gravedigger (L. mobilensis). Based on the published study by Glon et al., both species occur only in Mississippi and Alabama and were thought to be confined between the Pascagoula and Mobile Rivers. The reported range of both species is currently less than 1,000 km2 and are among the most-narrow ranged species within the state of Mississippi. With only 5 known localities for each species in the state, further efforts to determine the status and complete distribution were needed. Herein, we report on the results from a burrowing crayfish survey at novel sites within and outside the known range of both focal species in Southeastern Mississippi. Surveys took place between January-August 2024, and at each site we collected crayfish using hand excavation, slurp guns, and dip nets. Additional notes on habitat, burrow abundance, and soil composition were also recorded. In total, 104 sites (22 via boat) were surveyed and 21 species were captured including both target species. Banded Mudbug was capture at 11 sites within the known range of the species; however, we failed to expand the species into notable areas outside its range. Lonesome Gravedigger was found at 16 sites, but was notably found in areas more north and west than previously reported. The results of the survey help to improve the understanding of Mississippi burrowing crayfish distribution and status in the state. Notes on other newsworthy crayfish research at the Mississippi Museum of Natural Science may also be discussed.
AUTHORS: Montana Fonner, West Liberty University; Zachary Loughman, West Liberty University
ABSTRACT: Cambarus veteranus (Guyandotte River Crayfish) has been in severe population decline since their description in 1914 by Faxon. In 2016 the species was listed as endangered under the Endangered Species Act due to a widespread range reduction. The major contributing factor to this decline is siltation caused by both historic and current logging and mining operations. C. veteranus occupies the interstitial spaces between slab boulders and the benthos. Siltation fills the interstitial space both, smothering live crayfish and reducing habitat availability by cementing slab boulders into the stream bed. C. veteranus is endemic to the Upper Guyandotte River Basin. Historically C. veteranus was found in 8 tributaries of the mainstem of the Upper Guyandotte River. Today C. veteranus is only found in one historic tributary, Pinnacle Creek. More recently, another stream, Clear Fork/Laurel Fork, was found to harbor populations of C. veteranus. Despite the conservation standing of C. veteranus a comprehensive habitat study on the mainstem of the Upper Guyandotte River has not been conducted. This study aims to investigate the mainstem of the Upper Guyandotte River and Lower Pinnacle Creek to determine habitat quality. We recorded observations of anthropogenic degradation, such as siltation, bank instability, and pollution. Data collected will be used towards mitigation efforts in restoring habitat suitability within the study area for C. veteranus. In addition, habitat data collected along the mainstem was integrated in crayfish collection surveys, at possibly overlooked locales, which were determined to have potentially suitable habitats for C. veteranus.
AUTHORS: Cameron Haeffner, Southern Illinois University; Dr. Greg Whitledge, Southern Illinois University
ABSTRACT: Naturally occurring chemical markers in calcified structures, such as otoliths and fin rays or spines, have been commonly used in the study of fish environmental history, including identifying natal environments of wild fish, distinguishing stocked from wild fish, and inferring sources of invasive species. There are a few examples of the use of natural chemical markers in aquatic invertebrates, but this technique has not been used for crayfishes. Eye stalks have been used to estimate age of some crustaceans and may contain a microchemical record of crayfish environmental history, although this has not been tested. The objectives of this study are to determine whether crayfish eye stalks reflect microchemical (Sr:Ca, Ba:Ca) signatures of water, whether water-eye stalk microchemistry relationships differ among species, and whether this structure retains microchemical signals of previously occupied environments following crayfish transfer or molting. Four species of crayfish (Faxonius virilis, F. illinoiensis, F. luteus, and F. punctimanus) were collected from several streams in Missouri and Illinois with different water microchemical signatures. A laboratory study was also conducted in which crayfish were transferred between waters with different Sr:Ca ratios to assess signature retention. Eye stalks were sectioned and analyzed using laser ablation-ICPMS. If eye stalks contain a microchemical record of crayfish environmental history as anticipated, this technique could potentially be used to reconstruct environmental history (e.g., origin, movement) of crayfishes in the wild and may also be useful for inferring sources of non-native species.
AUTHORS: Anna Raney, University of Missouri and Florida Fish and Wildlife Conservation Commission; Jacob Westhoff, U.S. Geological Survey, Missouri Cooperative Fish and Wildlife Research Unit, School of Natural Resources
ABSTRACT: Crayfish invasions are among the top global threats to native crayfish populations. In Missouri, cross-basin introductions have impacted multiple endemic species. The Saint Francis River crayfish (Faxonius quadruncus) and Big Creek crayfish (F. peruncus), endemic to the upper Saint Francis River (USFR) drainage in Missouri, are currently under threat of extinction due to introductions of Woodland Crayfish (F. hylas) from nearby drainages. Previous research has documented reduced abundances and range reductions for both native species in reaches invaded by Woodland Crayfish. However, the entire ranges of the native species have not been systematically sampled prior to this study, and past survey data documenting the invasion are over 15 years old. Management agencies need updated information to create an informed recovery plan for the two threatened species. Using a stratified random sampling design, we conducted a basin-wide distribution survey at 96 sites across the USFR drainage in 2022-2023. We incorporated presence-absence data from this survey with coarse-scale environmental variables into random forest, boosted regression, and spatial stream network models to create species distribution models for the two endemic species and the invasive Woodland Crayfish population. Additionally, we used targeted, intensive sampling to locate the leading edges of invasion in six streams. During these efforts, we discovered and mapped additional invasions in two major tributaries to the USFR drainage and documented a 1.4 km range expansion upstream from the 2009 leading edge in Orr Hollow Creek. The Woodland Crayfish is now present in most major tributaries on the left side of the basin as well as multiple locations in the mainstem river. Despite these range expansions, small impoundments at multiple locations appeared to harbor refuge populations of endemic crayfish based on survey data. Results from this study can be used to identify refugia for native species and locate barriers to further invasion.
