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Knapp C.R.,John G. Shedd Aquarium | Knapp C.R.,San Diego Zoos Institute for Conservation Research | Alvarez-Clare S.,University of Florida | Perez-Heydrich C.,University of Florida

The relationship between dispersal and predatorprey interactions in heterogeneous landscapes is an underappreciated factor influencing species persistence. This relationship, however, is critical for understanding population dynamics and for implementing management strategies for species. We investigated the influence of habitat heterogeneity and dispersal patterns on neonate survival for the iguana Cyclura cychlura cychlura inhabiting Andros Island in the Bahamas. Contrary to our hypothesis, there was a clear survival advantage for neonates that spent more time in open mangrove habitat than relatively more closed-canopy habitats, most likely because of fewer primary predators in mangroves relative to other habitats. Snake predation was the most significant cause of mortality for neonates dispersing away from nest sites and was highest during the first week after release. The probability of survival to 28 days ranged from 16.7 to 28.4. Most neonates displayed rapid, nearly linear movements away from nests for a minimum of 14 to 21 days. Mean straight-line distance away from nest sites for surviving neonates was 601 m. There was a significant positive relationship between mean daily movement rates away from nests and days survived. We suspect that the initial and rapid movements away from nests reduce relative predation by dispersing neonates from a zone where predators learn to exploit them. Our results have implications for translocation programs targeting endangered insular iguanas throughout the Neotropics because historically only the presence of non-native mammalian predators was used as a metric to evaluate potential translocation sites. © 2010 by the American Society of Ichthyologists and Herpetologists. Source

Opriessnig T.,Iowa State University | Shen H.G.,Iowa State University | Bender J.S.,Iowa State University | Boehm J.R.,John G. Shedd Aquarium | Halbur P.G.,Iowa State University
Journal of Comparative Pathology

In order to determine the diversity and pathogenicity of Erysipelothrix spp. isolates recovered from marine fish, a harbour seal (Phoca vitulina) and the marine environment, 14 isolates were characterized by genotyping, serotyping, determination of the surface protective antigen (spa) gene type and assessment of virulence in a pig bioassay. All 14 isolates were Erysipelothrix rhusiopathiae. Isolates were determined to be of serotypes 2 (n = 3), 3 (n = 1), 4 (n = 1), 12 (n = 1), 15 (n = 1) or 21 (n = 6), and one isolate cross-reacted with serotypes 5 and 21. The spa gene analysis determined that 64.3% (n = 9) were spaA and 35.7% (n = 5) were spaB1. In pigs, 10/14 isolates induced small plaques to diamond-shaped cutaneous lesions consistent with Erysipelothrix spp. infection. The results of this study indicate that the marine E. rhusiopathiae isolates have greater genetic and antigenic diversity than pig isolates and are capable of inducing classical skin lesions in pigs. © 2012 Elsevier Ltd. Source

Hyatt M.W.,Georgia Aquarium | Anderson P.A.,The Florida Aquarium Center for Conservation | O'Donnell P.M.,Rookery Bay National Estuarine Research Reserve | Berzins I.K.,John G. Shedd Aquarium
Comparative Biochemistry and Physiology - A Molecular and Integrative Physiology

Blood gasses of wild bonnethead, bull, and lemon sharks were measured with the i-STAT clinical analyzer with the CG4+ cartridge immediately after capture; and again immediately prior to release after tagging, handling and morphometric measurements were taken. Relative reference ranges of post-capture status were established. Among species, stress response to capture was similar for all parameters; however, pH declined and lactate concentrations rose over time, indicating continued insult from capture and/or response to additional handling stress. pCO 2 rose faster for S. tiburo than for C. leucas, and lactate concentrations rose faster for S. tiburo than for N. brevirostris. All species caught in gillnets experienced lower pH and higher lactate concentrations than on longlines. Discriminant analysis justified the use of blood gas analysis to assess physiological stress induced by different capture methods. From these results, we recommend 1) that gear be monitored closely and sharks be removed immediately, or suboptimally, that gear is deployed for the shortest soak time possible; 2) longline over gillnet gear; and 3) extra caution with sensitive species (e.g., S. tiburo), which may include the administration of blood buffers and other therapeutics if a shark is beyond the limits of relative reference ranges reported here. © 2011 Elsevier Inc. Source

Swain T.D.,Northwestern University | DuBois E.,Northwestern University | Gomes A.,Northwestern University | Stoyneva V.P.,Northwestern University | And 18 more authors.
BMC Ecology

Background: At the forefront of ecosystems adversely affected by climate change, coral reefs are sensitive to anomalously high temperatures which disassociate (bleaching) photosynthetic symbionts (Symbiodinium) from coral hosts and cause increasingly frequent and severe mass mortality events. Susceptibility to bleaching and mortality is variable among corals, and is determined by unknown proportions of environmental history and the synergy of Symbiodinium- and coral-specific properties. Symbiodinium live within host tissues overlaying the coral skeleton, which increases light availability through multiple light-scattering, forming one of the most efficient biological collectors of solar radiation. Light-transport in the upper ~200 μm layer of corals skeletons (measured as 'microscopic' reduced-scattering coefficient, μ'S,m), has been identified as a determinant of excess light increase during bleaching and is therefore a potential determinant of the differential rate and severity of bleaching response among coral species. Results: Here we experimentally demonstrate (in ten coral species) that, under thermal stress alone or combined thermal and light stress, low-μ'S,m corals bleach at higher rate and severity than high-μ'S,m corals and the Symbiodinium associated with low-μ'S,m corals experience twice the decrease in photochemical efficiency. We further modelled the light absorbed by Symbiodinium due to skeletal-scattering and show that the estimated skeleton-dependent light absorbed by Symbiodinium (per unit of photosynthetic pigment) and the temporal rate of increase in absorbed light during bleaching are several fold higher in low-μ'S,m corals. Conclusions: While symbionts associated with low-μ'S,m corals receive less total light from the skeleton, they experience a higher rate of light increase once bleaching is initiated and absorbing bodies are lost; further precipitating the bleaching response. Because microscopic skeletal light-scattering is a robust predictor of light-dependent bleaching among the corals assessed here, this work establishes μ'S,m as one of the key determinants of differential bleaching response. © 2016 Swain et al. Source

Lesniak T.C.,John G. Shedd Aquarium | Lesniak T.C.,Northeastern Illinois University | Schirmer A.E.,Northeastern Illinois University | Knapp C.R.,Daniel erther Center For Conservation Research
Zoo Biology

We conducted a temperature-dependent reproductive study on Yellow Stingrays (Urobatis jamaicensis) at the John G. Shedd Aquarium, Chicago, Illinois. A group of eight and six female rays were mated in 22°C ("cold") and 27°C ("warm") water, respectively, over a two-year period. Mating behavior, gestation length, pup yields, body condition indices, and activity levels were compared throughout both temperature trials. Mating behavior (e.g., pre-copulatory pursuits and behavior) did not differ between temperature trials. Cold trial gestation was incomplete and yielded no pups, while the warm trial resulted in three successful births and one stillborn birth. Body condition indices and overall activity were significantly decreased in the cold trials. These data suggest consequences for rearing Yellow Stingrays in cooler water and should aid in successful reproduction of U. jamaicensis at zoos and aquariums. Zoo Biol. 34:33-39, 2015. © 2014 Wiley Periodicals, Inc. Source

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