375 Poster Session I, Event Center – The Snowbird Center, Friday 26 July 2019 Maria Sabando1, Yannis Papastamatiou1, Guillaume Rieucau2, Darcy Bradley3, Jennifer Caselle3 1Florida International University, Miami, FL, USA, 2Louisiana Universities Marine Consortium, Chauvin, LA, USA, 3University of California, Santa Barbara, Santa Barbara, CA, USA Reef Shark Behavioral Interactions are Habitat Specific Dominance hierarchies and competitive behaviors have been studied in several species of animals that includes mammals, birds, amphibians, and fish. Competition and distribution model predictions vary based on dominance hierarchies, but most assume differences in dominance are constant across habitats. More recent evidence suggests dominance and competitive advantages may vary based on habitat. We quantified dominance interactions between two species of sharks Carcharhinus amblyrhynchos and Carcharhinus melanopterus, across two different habitats, fore reef and back reef, at a remote Pacific atoll. We used Baited Remote Underwater Video (BRUV) to observe dominance behaviors and quantified the number of aggressive interactions or bites to the BRUVs from either species, both separately and in the presence of one another. Blacktip reef sharks were the most abundant species in either habitat, and there was significant negative correlation between their relative abundance, bites on BRUVs, and the number of grey reef sharks. Although this trend was found in both habitats, the decline in blacktip abundance with grey reef shark presence was far more pronounced in fore reef habitats. We show that the presence of one shark species may limit the feeding opportunities of another, but the extent of this relationship is habitat specific. Future competition models should consider habitat-specific dominance or competitive interactions. ____________________________________________________________________________ 592 Poster Session II, Event Center – The Snowbird Center, Saturday 27 July 2019 Daniel Saenz1, Toby Hibbitts2, Cory Adams1 1Southern Research Station, US Forest Service, Nacogdoches, Texas, USA, 2Department of Wildlife and Fisheries Sciences, Biodiversity Research and Teaching Collections, Texas A&M University, College Station, Texas, USA Calling Phenology of the Southern Crawfish Frog (Lithobates areolatus) The crawfish frog (Lithobates areolatus) spends most of its time in or near crawfish burrows, making it difficult to detect except when breeding. During the breeding season, however, they migrate to breeding wetlands and have exceptionally loud advertisement calls that allow auditory surveys to be conducted with relative ease. Our study is an attempt to learn about crawfish frog seasonal calling phenology, diel calling activity, and the exogenous factors that influence calling in the southern part of its range, the coastal prairie of Texas. We conducted auditory surveys for crawfish frogs and collected environmental data at the Attwater Prairie Chicken National Wildlife Refuge in Austin and Colorado Counties, Texas, from January 2013 through December 2018. After six years of daily surveys, our results revealed that there is an approximately 7- month window, each year, when crawfish frogs can call. However, crawfish frogs only call for a few days each year and there is significant inter-annual variation in the timing of the breeding activity. Our analyses suggest that the timing of crawfish frog calling activity is driven by several important abiotic factors. Breeding pond water depth, relative humidity, and rainfall have a significant positive relationship with crawfish frog calling and water temperature and wind speed are negatively associated. We suggest that crawfish frogs from the coastal prairies of Texas have an exceptionally long breeding season to be able to successfully breed when conditions are favorable in an unpredictable and sometimes harsh environment. ____________________________________________________________________________ 793 Ichthyology Systematics II, Cottonwood A-D – The Snowbird Center, Sunday 28 July 2019 Michael Sandel1, Andres Aguilar2, David Neely3, Thaddaeus Buser4 1The University of West Alabama, Livingston, Alabama, USA, 2California State University Los Angeles, Los Angeles, California, USA, 3Tennesee Aquarium Conservation Institute, Chattanooga, Tennessee, USA, 4Oregon State University, Corvallis, Oregon, USA Phylogenomic Interrelationships and Osteology of Baikal Sculpins with a Comparison of Perciform Adaptive Radiations Lake Baikal is the oldest and largest freshwater ecosystem on Earth. The sculpins (Perciformes: Cottidae) of Lake Baikal represent the most diverse adaptive radiation of lacustrine fishes outside of the tropics. We present the first resolved phylogeny of 12 Baikalian sculpin genera with complete sampling of all extant species, inferred from complete mitochondrial genomes and over 100,000 single nucleotide polymorphisms (SNPs). We also report comparative analyses of 25 complete exomes, assembled from illumina sequencing over 300,000 capture targets. Results of phylogenetic analyses reveal non-monophyly of a number of taxa, including the family Abyssocottidae. We present a comprehensive set of osteological characters inferred from microCT scans, and map the evolution of osteological characters on the phylogeny. Results of comparative genomic analyses identify a number of important gene pathways shared with other perciform radiations. We discuss a subset of these pathways, including those involving neural crest development and oxidative phosphorylation, as they relate to the diversification of the Baikal Sculpin Radiation. ____________________________________________________________________________ 81 Poster Session I, Event Center – The Snowbird Center, Friday 26 July 2019 Theresa Santos1, João Veloso1, Bruno Macena1,2, Fabio Hazin1 1Universidade Federal Rural de Pernambuco, Recife, PE, Brazil, 2Universidade dos Açores, Horta, Faial, Portugal Foraging aspects of Cookiecutter Shark (Isistius sp.) in an equatorial Mid-Atlantic archipelago The Cookiecutter Shark (Isistius sp.) is a small squaloid shark found in the pelagic waters of tropical and sub-tropical oceans. The shark’s unique mouth, teeth and tongue morphology leaves a circular bite on their preys. However, very little is known about their foraging ecology and population. The present study aimed to understand the Cookiecutter Shark foraging ecology through the patterns and frequency of bite scars on fishes in Saint Peter and Saint Paul Archipelago (SPSPA). Many pelagic fishes were caught by the commercial fleet that operates nearby SPSPA, some of them presented wounds from cookiecutter shark bites. The number of bites, diameter, and healing stage were assessed. Based on the high frequency of bite scars, the Wahoo (Acanthocybium solandri) was selected for further analysis. The estimated size of sharks that inflicted bites on pelagic fish was calculated from the diameter of bite scars, by using a linear regression of the shark’s mouth width (MW) vs. total length (TL) TL= 4.5 (MW) + 82.8, where TL is shark total length (mm) and MW is shark mouth width (mm). A total of 100 Wahoos were analyzed; the wounds were found on lateral (71.6%), ventral (21.7%) and dorsal (6.7%) sides. The estimated size of the Cookiecutter Sharks that inflicted wounds ranged from 127 mm to 308 mm TL, and average size was 210 ±35 mm, suggesting the Wahoos were attacked by rather large sharks, for the species. The present study provides an insight into the foraging ecology of this elusive species. ____________________________________________________________________________ 120 Poster Session II, Event Center – The Snowbird Center, Saturday 27 July 2019 Rachel Santymire1, Allison Sacerdote-Velat2, Andrew Gygli3, Douglas Keinath3, Sinlan Poo4, Kristin Hinkson4, Elizabeth McKeag3 1Conservation and Science Department, Lincoln Park Zoo, Chicago, IL, USA, 2Chicago Academy of Sciences, Chicago, IL, USA, 3US Fish and Wildlife Service, Wyoming Ecological Services Field Office, Cheyenne, WY, USA, 4Conservation and Research Department, Memphis Zoo, Memphis, TN, USA Using dermal cortisol to measure the stress physiology of wild and captive Wyoming toads (Anaxyrus baxteri) We investigated disease, environmental conditions and stress physiology relationships in endangered Wyoming toads (Anaxyrus baxteri) using a novel, noninvasive dermal swabbing method to measure glucocorticoids. We aimed to validate use of dermal swabs to measure cortisol via enzyme immunoassay using adrenocorticotropic hormone (ACTH) challenge on 8 captive Wyoming toads (4 ACTH: 2M, 2F and 4 saline as controls: 2M, 2F); compare fecal glucocorticoid metabolites (FGMs) pre- and post-ACTH (1M, 1F); and investigate dermal cortisol across reintroduction sites with varying population success and disease prevalence. In females, saline resulted in two elevated swabs at 0 min (2.2-fold) and 60 mins (13.3-fold) and ACTH resulted in 2 (4.6-fold at 0 min and 3.0-fold at 90 min) and 3 elevated swabs (10.7-fold at 0 min, 3.4-fold at 30 min and 3.9-fold at 60 min). In males, saline resulted in 1 elevated swab (8.6-fold) at 0 mins. For males, ACTH resulted in elevated swabs at 45 mins (4.9 fold) and 60 mins (3.1-fold) post-injection, respectively. Saline produced no change in FGMs post-injection; however, the male had elevated FGMs (7.6-fold) 2 days post-ACTH and female had elevated FGMs (1.6-fold) 4 days post-ACTH. Dermal cortisol was similar across reintroduction sites; however, wild males at the Mortenson site