Common bottlenose dolphin, Tursiops truncatus, seasonal habitat use and associations with habitat characteristics in Roanoke Sound, North Carolina

Understanding how habitat characteristics influence common bottlenose dolphin, Tursiops truncatus, distribution and behavior can be useful for conservation. The dolphin community in Roanoke Sound, North Carolina primarily exhibits seasonal residency and there is limited information on their habitat use. The objectives of this study were to increase habitat use knowledge and determine the relationship between habitat characteristics and dolphin distribution using standardized photographic-identification data (2009 – 2017). A hot spot (Getis-Ord Gi*) analysis showed dolphins frequently use the southern region containing the mouth of the estuary for feeding and traveling. Habitat characteristics were modeled with zero-altered gamma (ZAG), generalized linear (GLM), and generalized additive (GAM) models to predict dolphin group density. Models showed that groups were more likely to be present in areas with greater benthic slope variation and shallow areas closer to land, and that different habitat characteristics were associated with feed, social, and travel activities. This study suggests that Roanoke Sound provides a seasonal foraging area and travel corridor between the estuaries and coastal waters. This information contributes baseline knowledge of how habitat potentially influences dolphin distribution and behavior which can be useful for management and conservation, especially in areas where habitat changes and impacts need to be assessed

Exposure to paper mill effluent at a site in North Central Florida elicits molecular-level changes in gene expression indicative of progesterone and androgen exposure.

Endocrine disrupting compounds (EDCs) are chemicals that negatively impact endocrine system function, with effluent from paper mills one example of this class of chemicals. In Florida, female Eastern mosquitofish (Gambusia holbrooki) have been observed with male secondary sexual characteristics at three paper mill-impacted sites, indicative of EDC exposure, and are still found at one site on the Fenholloway River. The potential impacts that paper mill effluent exposure has on the G. holbrooki endocrine system and the stream ecosystem are unknown. The objective of this study was to use gene expression analysis to determine if exposure to an androgen receptor agonist was occurring and to couple this analysis with in vitro assays to evaluate the presence of androgen and progesterone receptor active chemicals in the Fenholloway River. Focused gene expression analyses of masculinized G. holbrooki from downstream of the Fenholloway River paper mill were indicative of androgen exposure, while genes related to reproduction indicated potential progesterone exposure. Hepatic microarray analysis revealed an increase in the expression of metabolic genes in Fenholloway River fish, with similarities in genes and biological processes compared to G. holbrooki exposed to androgens. Water samples collected downstream of the paper mill and at a reference site indicated that progesterone and androgen receptor active chemicals were present at both sites, which corroborates previous chemical analyses. Results indicate that G. holbrooki downstream of the Fenholloway River paper mill are impacted by a mixture of both androgens and progesterones. This research provides data on the mechanisms of how paper mill effluents in Florida are acting as endocrine disruptors

Whitespotted eagle ray (Aetobatus narinari) age and growth in wild (in situ) versus aquarium-housed (ex situ) individuals: Implications for conservation and management

Elasmobranchs typically display slow growth, late maturity and low fecundity life history characteristics, making them vulnerable to fishing pressures and environmental perturbations. The whitespotted eagle ray (Aetobatus narinari), a large pelagic migratory ray with an endangered status on the IUCN Red List, fits this pattern based on available literature. Historically, age and growth parameters for this ray have been reported through vertebral ageing methods. However, the periodicity of vertebrate band pair formation, which is used for ageing, has not been validated for this species, making ageing accuracy and thus the resulting growth parameters uncertain. In this study, we used both a frequentist and Bayesian method of estimating sex-specific von Bertalanffy growth parameters (DW∞, k) in wild recaptured versus aquarium-housed rays. Additionally, we estimated growth from repeated measurement data collected from aquarium-housed rays, as an alternative approach to obtain growth parameters while allowing for individual variability. Between 2009 and 2020, 589 whitespotted eagle rays were caught, measured, tagged and released along the southwest coast of Florida. Of these rays, 34 were recaptured between 5–1413 days at liberty. Nineteen additional rays were collected during the same period, transported and maintained at Georgia Aquarium, Atlanta, where they were regularly weighted and measured. Data from Association of Zoos and Aquariums accredited facilities provided prior information on maximum size for the Bayesian estimations, and size at birth, size at maturity, and maximum life span. These data were used to plot and interpret von Bertalanffy growth curves. Wild whitespotted eagle rays were found to grow faster and mature earlier than previously thought, with Bayesian estimates of k = 0.28 year-1 in females, and k = 0.30 year-1 in males. Aquarium-housed individuals seemed to grow slower and reach smaller sizes, although data provided by the aquariums showed variable growth patterns depending on the facility. Longevity was estimated at 14-15 years in wild rays while maximum lifespan observed in aquariums was 19-20+ years. Life history parameters and growth trajectories generated from this study offer valuable information to aid with future conservation management strategies of this endangered species.ISSN:2296-774

Marcação, padrões variados e comportamento dos golfinhos franciscanas (Pontoporia blainvillei) fora da Argentina e do Brasil: Considerações para a conservação

The franciscana dolphin, Pontoporia blainvillei, is one of the most threatened cetaceans in the Southwestern Atlantic. Within their limited coastal range off Argentina, Uruguay, and Brazil, franciscanas face human activities, including artisanal gillnet fishing and coastal development. A lack of information on ranging patterns, population structure, and behavior for informing management led to efforts to develop and apply approaches to tag franciscanas in Argentina (Bahía Samborombon [BS], Bahía San Blas [BSB]) and Brazil (Baía Babitonga [BB]) during 2005–2013. Findingsfrom VHF tags deployed in BS in 2005 during feasibility tests for catching and handling franciscanas for tagging suggested residency over periods of weeks. Subsequently, satellite-linked tags confirmed patterns of residency at each site. Home range size varied, with ranges of 5–7 km2 for BB, 51–312 km2 for BS, and 49–1,014 km2 for BSB. Diving patterns varied across sites, with the animals using the entire water column, exposing them to fishing nets regardless of the depth at which the nets were set. Tracking durations and follow-up observations indicated that this research approach is useful for studies of franciscanas. Small, definable ranges facilitate relating specific geographically based threats to appropriate population units, increasing the potential for effective conservation.info:eu-repo/semantics/publishedVersio

Common bottlenose dolphin, Tursiops truncatus, seasonal habitat use and associations with habitat characteristics in Roanoke Sound, North Carolina

Understanding how habitat characteristics influence common bottlenose dolphin, Tursiops truncatus , distribution and behavior can be useful for conservation. The dolphin community in Roanoke Sound, North Carolina primarily exhibits seasonal residency and there is limited information on their habitat use. The objectives of this study were to increase habitat use knowledge and determine the relationship between habitat characteristics and dolphin distribution using standardized photographic-identification data (2009 – 2017). A hot spot (Getis-Ord Gi*) analysis showed dolphins frequently use the southern region containing the mouth of the estuary for feeding and traveling. Habitat characteristics were modeled with zero-altered gamma (ZAG), generalized linear (GLM), and generalized additive (GAM) models to predict dolphin group density. Models showed that groups were more likely to be present in areas with greater benthic slope variation and shallow areas closer to land, and that different habitat characteristics were associated with feed, social, and travel activities. This study suggests that Roanoke Sound provides a seasonal foraging area and travel corridor between the estuaries and coastal waters. This information contributes baseline knowledge of how habitat potentially influences dolphin distribution and behavior which can be useful for management and conservation, especially in areas where habitat changes and impacts need to be assessed

Significantly differentially regulated biological processes in female <i>G. holbrooki</i> residing downstream of a paper mill as compared to a control site as determined by gene set enrichment and gene ontology (GO) analyses.

a<p> Percentage of genes within the GO category that were significantly differentially regulated between Econfina and Fenholloway groups.</p>b<p> Percentage of genes within the GO category that were not significantly differentially regulated between Econfina and Fenholloway groups.</p><p>Significantly differentially regulated biological processes in female <i>G. holbrooki</i> residing downstream of a paper mill as compared to a control site as determined by gene set enrichment and gene ontology (GO) analyses.</p

Common Bottlenose Dolphin, \u3ci\u3eTursiops truncatus\u3c/i\u3e, Seasonal Habitat Use and Associations With Habitat Characteristics In Roanoke Sound, North Carolina

Understanding how habitat characteristics influence common bottlenose dolphin, Tursiops truncatus, distribution and behavior can be useful for conservation. The dolphin community in Roanoke Sound, North Carolina primarily exhibits seasonal residency and there is limited information on their habitat use. The objectives of this study were to increase habitat use knowledge and determine the relationship between habitat characteristics and dolphin distribution using standardized photographic-identification data (2009 – 2017). A hot spot (Getis-Ord Gi*) analysis showed dolphins frequently use the southern region containing the mouth of the estuary for feeding and traveling. Habitat characteristics were modeled with zero-altered gamma (ZAG), generalized linear (GLM), and generalized additive (GAM) models to predict dolphin group density. Models showed that groups were more likely to be present in areas with greater benthic slope variation and shallow areas closer to land, and that different habitat characteristics were associated with feed, social, and travel activities. This study suggests that Roanoke Sound provides a seasonal foraging area and travel corridor between the estuaries and coastal waters. This information contributes baseline knowledge of how habitat potentially influences dolphin distribution and behavior which can be useful for management and conservation, especially in areas where habitat changes and impacts need to be assessed

Gene expression profile comparisons between Fenholloway (PME) and reference site (Econ) female <i>G. holbrooki</i> and female <i>G. holbrooki</i> exposed to the androgen 17β-trenbolone (TB) or the vehicle control (C).

<p>This set of genes were differentially expressed between the PME, Econfina, and TB groups over the lab controls with at least a 1.5-fold difference of expression over the lab control and was expressed in the same direction in those groups. Data were median-centered by gene and clustered using spearman correlation and centroid linkage. Yellow genes are more highly expressed than the gene average and blue genes are expressed at a lower level than the gene average.</p

Anal fin elongation and bone segment formation in anal fin ray 3 of female Eastern mosquitofish (<i>Gambusia holbrooki</i>) collected from the Fenholloway and Econfina Rivers.

<p>Data are repsresented as (A) Mean (± standard deviation) of all collection events and, (B) Distribution of anal fin elongation classes between both paper mill exposed (Fenholloway) and reference (Econfina) field sites. An asterisk indicates statistical significance between the two groups as determined using a Student's t-test with p<0.05. For anal fin elongation levels there was an N of 46 and 50 from the Fenholloway and Econfina rivers respectively and a subset N of 4 from both sites for the bone segment evaluation.</p

Results of progesterone receptor (PR) and androgen receptor (AR) GeneBLAzer assays for concentrated water samples collected downstream of the Fenholloway River paper mill and the Econfina River conservation area.

<p>The graph bars represent the mean of three replicates from each dilution for the PR (A) and AR (B) assays. Error bars represent standard deviation of the three replicates per assay. The dose-responses of levonorgestrel, progesterone, and 17β-trenbolone (C) were also evaluated by the AR assay.</p