Session 49: Ichthyology Genetics (first 5)/ Reproductive Biology (last 1)Room: Ballroom 111C2022-07-31 13:45 - 15:00 |
| Moderator: Chris Martin |
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1. 13:45 Epigenetic Evidence of Oil Exposure in Laboratory Reared and Wild Red Drum (Sciaenops ocellatus). Andrew T. Fields*, Texas A&M University - Corpus Christi; Natalie N. Beeken, Texas A&M University - Corpus Christi; Christopher M. Hollenbeck, Texas A&M University - Corpus Christi; Dana Wetzel, Mote Marine Laboratory; David S. Portnoy, Texas A&M University - Corpus Christi andrew.fields@tamucc.edu
Red drum (Sciaenops ocellatus) are an economically and ecologically important fish in the western North Atlantic, especially in the Gulf of Mexico. The Deepwater Horizon oil spill released over 4.9 million barrels of crude oil into the Gulf of Mexico, contaminating 847 miles of coastline where juvenile red drum are estuarine obligates. Studies have shown that oil exposure can have lethal effects, but it is unclear if sublethal, transgenerational effects can be caused by oil exposure. One mechanism for transgenerational effects would be alterations to the epigenome. Using bsRADseq, we compared patterns of methylation between drum exposed to weathered Deepwater Horizon oil in the laboratory and wild caught red drum from Louisiana estuaries. In laboratory fish, patterns of methylation were significantly different between the oil and control treatments at 2,130 CpG sites across 1,451 genomic locations. Of these loci, 744 were significantly associated with levels of total polyaromatic hydrocarbon (tPAH) measured in the liver of wild drum. Approximately 30% of these loci found were found in genetic pathway annotations, indicating differential methylation in olfactory, ocular and cell to cell signaling pathways. Consistent with these results, alterations in the development of eyes, olfaction and neurological responses have been demonstrated in fish exposed to oil in lab experiments. Epigenetic biomarkers could aid in monitoring environmental events and provide insight into how oil affects exposed animals’ cellular pathways and long-term health of marine species. |
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2. 14:00 How Long? Examining Selection in the Evolution of Elongation among Gobies. Kendall Johnson*, Texas A&M University - Corpus Christi; Luke Tornabene, University of Washington; Frank Pezold, Texas A&M University - Corpus Christi kjohnson47@islander.tamucc.edu
Gobies (Gobiidae+Oxudercidae) are two of the most species-rich and ecologically diverse families of teleosts. An early period of rapid diversification led to the evolution of a remarkable variety of ecologies and morphologies, making them ideal subjects for testing hypotheses regarding morphological adaptation to different environments and lifestyles. For the majority of these adaptations, we lack even a cursory understanding of what genes may be responsible for morphological change and what is the role of selection on these genes. Elongation of the body, whether by increase in the number of vertebrae or lengthening of vertebrae, is an adaptation that appears in both families. Elongated taxa occupy a variety of ecologies and habitats from hovering in the water column to burrowing into the substrate. The goal of this study was to examine the strength of natural selection on genes associated with the evolution of body elongation in gobies. Using a phylogeny produced with gene-capture data coupled with analyses of lineage-specific patterns in synonymous/nonsynonymous substitutions, we tested whether specific protein-coding genes were under intensified or relaxed selection in lineages exhibiting different types of elongation. We found more genes were under relaxed selection in taxa with increased vertebral segmentation than those with longer vertebrae, and that the genes under significant relaxation or intensification of selection in elongated taxa differed between each type of elongation. While functions relating to anatomical development were enriched in genes associated with elongation, the role many genes have in the evolution of elongation remain to be further explored. |
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3. 14:15 Genetic approaches reveal a healthy population and an unexpected origin for Foskett Spring Speckled Dace. Brian Sidlauskas*, Oregon State University; Hakan Aydo?an, Oregon State University; Samarth Mathur, The Ohio State University; Andrew Black, Oregon State University brian.sidlauskas@oregonstate.edu
Oregon’s Foskett Spring harbors a morphologically and genetically distinctive population of Speckled Dace (Rhinichthys osculus) long considered to have inhabited a desert spring pool just a few meters across since isolation at the end of the pluvial period 10,000 years ago. Though recently delisted from the Federal list of threatened species thanks to successful implementation of a recovery plan, maintenance of healthy population sizes appears to depend upon manual removal of encroaching vegetation. That dependence raises the question of how Foskett Dace persisted for so long in their tiny habitat prior to human management. To monitor the population’s health and investigate the phenomenon of its persistence, we used 3300 single nucleotide polymorphisms to assess genetic diversity and demographic history among dace in Foskett Spring and in nearby streams, including a newly discovered population from Nevada’s Coleman Creek. The dace inhabiting Foskett Spring are genetically healthy, with an effective population size well over 1000 and an inbreeding coefficient near zero. Principal component and Admixture analyses identified three distinct clusters of dace in the region, with Foskett Dace more similar to the newly discovered Nevada population than to the dace in the Oregon streams previously thought to be their closest living relatives. These results indicate the Nevada population as the ancestral source of the lineage that seeded Foskett Spring, suggest a more recent isolation than previously suspected, and help to solve the enigma of persistence by shortening the duration over which Foskett Dace have inhabited their isolated spring pool. |
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4. 14:30 Indian River Lagoon eDNA Metabarcoding: Community Structure and Biodiversity Across a Water Quality Gradient. Jeff Eble*, Florida Institute of Technology; Carly McCall, Florida Institute of Technology; Girish Kumar, University of Central Florida; Michelle Gaither, University of Central Florida jff.eble@gmail.com
To improve understanding and management of Indian River Lagoon marine biodiversity, environmental DNA (eDNA) sampling was coupled with next-generation DNA sequencing to provide information on species occurrence and community diversity across a pronounced water quality gradient. Non-target amplification of abundant plankton limited the resolution of crustacean and metazoan specific genetic markers. A combined 89 fishes were successfully detected in mixed samples containing a high concentration of plankton. The resulting fish biodiversity data were used to establish a baseline to track community response to ongoing and proposed water quality restoration initiatives. The initial baseline improves understanding of biodiversity patterns in the lagoon, including highlighting regional drivers of fish diversity and the impact of declining water quality and frequent harmful algal bloom outbreaks on lagoon fishes. |
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5. 14:45 Reproductive biology of Moncholo Hoplias malabaricus in the Cienaga Grande de Lorica, Colombia. Yarima J. Valle-Díaz, Fishery Biology Research Laboratory-FBRL, Department of Aquatic Sciences. University of Cordoba; Ibis P. Espitia-Hernández, Fishery Biology Research Laboratory-FBRL, Department of Aquatic Sciences. University of Cordoba; Jesús Vargas-González, Fishery Biology Research Laboratory-FBRL, Department of Aquatic Sciences. University of Cordoba; Juan J. Hernández-Correa, SEPEC; Ángel L. Martínez-González, Fishery Biology Research Laboratory-FBRL, Department of Aquatic Sciences. University of Cordoba; Fredys F. Segura-Guevara, Fishery Biology Research Laboratory-FBRL, Department of Aquatic Sciences. University of Cordoba; Charles W. Olaya-Nieto, Fishery Biology Research Laboratory-FBRL, Department of Aquatic Sciences. University of Cordoba; Glenys Tordecilla-Petro*, Fishery Biology Research Laboratory-FBRL, Department of Aquatic Sciences. University of Cordoba colaya@correo.unicordoba.edu.co
To evaluate the reproductive biology of Moncholo Hoplias malabaricus in the Cienaga Grande de Lorica, Colombia, we analyzed 366 individuals collected between January and December 2018, with total length (TL) and total weight (TW) ranged between 18.9-38.1 cm TL and 62.0-667.0 grams, respectively, with mean catch length of 26.1 cm TL. The Vazzoler scale was used for the ovaries and sex ratio, maturity index, spawning season, length at first maturity, ovocites’s diameter and fecundity were estimated. We found 178 females and 188 males, with mean catch length of 26.1 cm TL. The results obtained suggest that the Moncholo is a fish with a female:male sexual ratio similar to what was expected, sexual dimorphism at size, oocyte development in more than two groups, with partial spawnings in a prolonged spawning season that extends throughout the year from February to December, independent of water level in the Cienaga Grande de Lorica, length at first maturity estimated in 25.5 cm TL for both sexes, large oocytes with 1467 ?m and low fecundity per spawning of 5306 oocytes associated with weight of their ovaries. |