Browsing by Author "Lyons, Kady"
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Item Costs of parthenogenesis on growth and longevity in ex situ zebra sharks Stegostoma tigrinum(Endangered Species Research, 2023-02-16) Adams, Lance; Lyons, Kady; Monday, Janet; Larkin, Elizabeth; Wyffels, JenniferThe zebra shark Stegostoma tigrinum, a popular aquarium fish, is an endangered species that is known to readily reproduce both sexually and through facultative parthenogenesis while in human care. Artificial insemination trials that took place between 2011 and 2013 resulted in the hatching of 2 sexually produced (herein heterozygotes) and 10 parthenogenetic sharks that allowed for a retrospective comparison of growth, feeding and longevity between offspring produced from 2 distinct reproductive modes. Parthenogenetic offspring were generally smaller at hatch than their heterozygous counterparts and, after the first several months post-hatch, failed to increase in mass and length at the same rate as heterozygotes. Parthenogenetic offspring exhibited non-normal swimming behaviors such as spiraling, spy hopping and head standing, which may have been correlated with a gradual decline in the ability of some sharks to properly suction feed. Median lifespan for the parthenotes was 1.05 yr (range: 0.27-6.64 yr); one of the heterozygotes lived to 2.37 yr of age, and the other was alive at the time of this writing in August 2022 and had reached reproductive maturity. By contrast, the 2 longest surviving parthenotes perished just prior to reaching sexual maturity (~5.5 and ~6.5 yr). Parthenogenesis has been documented among ex situ S. tigrinum maintained in aquariums across the globe, and this study demonstrates substantial negative costs to fitness in parthenogenetic offspring compared with their heterozygous siblings. The reduced fitness of parthenotes has implications for managing populations in human care as well as for in situ conservation efforts.Item Network Analysis Reveals Species-Specific Organization of Microbial Communities in Four Co-Occurring Elasmobranch Species along the Georgia Coast(Fishes, 2024-01-15) Lyons, Kady; Bedore, Christine N.; Carlisle, Aaron B.; Moniz, Lauren; Odom, Timothy L.; Ahmed, Rokeya; Greiman, Stephen E.; Freedman, Ryan M.Comparing co-occurring species may provide insights into how aspects of ecology may play a role in influencing their microbial communities. During the 2019 commercial shrimp trawl season off coastal Georgia, swabs of skin, gills, cloaca, and gut were taken for three species of batoids (Butterfly Ray, Bluntnose Stingray, and Atlantic Stingray) and one shark species (Atlantic Sharpnose) for high-throughput sequencing of the V4 region of the bacterial 16S rRNA gene. White muscle was analyzed for stable isotopes (δ13C and δ15N) to evaluate potential niche overlap in these four sympatric mesopredators. Significant differences were found in both δ13C and δ15N signatures across species, suggesting a degree of resource partitioning. When examined within tissue type, the host species had a weak effect on β-diversity for cloaca and skin, with no differences found for gill and gut samples. However, network analysis metrics demonstrated a stronger species-specific effect and distinct microbial community relationships were apparent between the shark and batoids, with the former having tighter networks for both internally- and externally-influenced tissues (gut/cloaca and skin/gills, respectively). Despite overlapping habitat use, species’ microbiomes differed in their organizational structuring that paralleled differences in stable isotope results, suggesting a mediating role of species-specific ecology on bacterial microbiomes.