Cortisol Reference Intervals.

<p>(a) Pre-sampling (<30 minutes elapsed time) and (b) post-sampling 95^th percentile reference intervals for serum cortisol (μg/dL) versus elapsed sampling time (min). Points represent measured pre-sampling <i>(N = 93)</i> and post-sampling <i>(N = 52)</i> serum cortisol values for bottlenose dolphins sampled in Sarasota Bay, FL 2000–2012; solid lines represent upper and lower bounds for the 95^th percentile.</p

Linear Mixed Models.

<p>Linear mixed model (LMM) results for covariates significantly associated with bottlenose dolphin serum concentrations of cortisol and aldosterone. Parameters in bold were significantly associated with cortisol concentrations (p<0.05). Abbreviations: N_o = number of observations; N_i = number of individuals; F = F statistic; df = numerator, denominator degrees of freedom.</p><p>^Log-transformed</p><p>Linear Mixed Models.</p

Descriptive Statistics.

<p>Descriptive statistics for hormone data for bottlenose dolphins sampled in Sarasota Bay, FL (2000–2012). Abbreviations: N_i = number of individuals; “% BDL” indicates the percentage of observations with hormone concentrations below respective detection limits.</p><p>*Values below detection limit calculated as ½ of the detection limit for the assay (Schwacke et al. 2009)</p><p>⁺Detection Limits: cortisol (0.2 μg/dL); aldosterone (11 pg/mL)</p><p>Descriptive Statistics.</p

Aldosterone Plots.

<p>(a) Pre-sampling aldosterone concentration (pg/mL) versus elapsed sampling time (min) and (b) pre-sampling aldosterone concentration (pg/mL) versus pre-sampling cortisol concentration (μg/dL) for bottlenose dolphins sampled in Sarasota Bay, FL 2000–2012 <i>(N = 103)</i>. Correlation coefficient (r) and statistical significance (p) reported for Spearman’s correlation test.</p

Serum Cortisol Reference Intervals.

<p>Serum cortisol (μg/dL) 95^th percentile reference intervals and associated 90% confidence intervals for free-ranging bottlenose dolphins sampled in less than 30 minutes following net deployment (pre-sampling) and dolphins sampled following veterinary procedures (post-sampling).</p><p>Serum Cortisol Reference Intervals.</p

Pre-Sampling Cortisol versus Elapsed Sampling Time.

<p>Pre-sampling cortisol concentration (μg/dL) vs. elapsed sampling time (min) for bottlenose dolphins sampled in Sarasota Bay, FL 2000–2012 <i>(N = 118)</i>.</p

Adrenal Hormones in Common Bottlenose Dolphins (<i>Tursiops truncatus</i>): Influential Factors and Reference Intervals

<div><p>Inshore common bottlenose dolphins (<i>Tursiops truncatus</i>) are exposed to a broad spectrum of natural and anthropogenic stressors. In response to these stressors, the mammalian adrenal gland releases hormones such as cortisol and aldosterone to maintain physiological and biochemical homeostasis. Consequently, adrenal gland dysfunction results in disruption of hormone secretion and an inappropriate stress response. Our objective herein was to develop diagnostic reference intervals (RIs) for adrenal hormones commonly associated with the stress response (i.e., cortisol, aldosterone) that account for the influence of intrinsic (e.g., age, sex) and extrinsic (e.g., time) factors. Ultimately, these reference intervals will be used to gauge an individual’s response to chase-capture stress and could indicate adrenal abnormalities. Linear mixed models (LMMs) were used to evaluate demographic and sampling factors contributing to differences in serum cortisol and aldosterone concentrations among bottlenose dolphins sampled in Sarasota Bay, Florida, USA (2000–2012). Serum cortisol concentrations were significantly associated with elapsed time from initial stimulation to sample collection (p<0.05), and RIs were constructed using nonparametric methods based on elapsed sampling time for dolphins sampled in less than 30 minutes following net deployment (95% RI: 0.91–4.21 µg/dL) and following biological sampling aboard a research vessel (95% RI: 2.32–6.68 µg/dL). To examine the applicability of the pre-sampling cortisol RI across multiple estuarine stocks, data from three additional southeast U.S. sites were compared, revealing that all of the dolphins sampled from the other sites (N = 34) had cortisol concentrations within the 95th percentile RI. Significant associations between serum concentrations of aldosterone and variables reported in previous studies (i.e., age, elapsed sampling time) were not observed in the current project (p<0.05). Also, approximately 16% of Sarasota Bay bottlenose dolphin aldosterone concentrations were below the assay’s detection limit (11 pg/mL), thus hindering the ability to derive 95th percentile RIs. Serum aldosterone concentrations from animals sampled at the three additional sites were compared to the detection limit, and the proportion of animals with low aldosterone concentrations was not significantly different than an expected prevalence of 16%. Although this study relied upon long-term, free-ranging bottlenose dolphin health data from a single site, the objective RIs can be used for future evaluation of adrenal function among individuals sampled during capture-release health assessments.</p></div

Health of Common Bottlenose Dolphins (Tursiops truncatus) in Barataria Bay, Louisiana, Following the <i>Deepwater Horizon</i> Oil Spill

The oil spill resulting from the explosion of the <i>Deepwater Horizon</i> drilling platform initiated immediate concern for marine wildlife, including common bottlenose dolphins in sensitive coastal habitats. To evaluate potential sublethal effects on dolphins, health assessments were conducted in Barataria Bay, Louisiana, an area that received heavy and prolonged oiling, and in a reference site, Sarasota Bay, Florida, where oil was not observed. Dolphins were temporarily captured, received a veterinary examination, and were then released. Dolphins sampled in Barataria Bay showed evidence of hypoadrenocorticism, consistent with adrenal toxicity as previously reported for laboratory mammals exposed to oil. Barataria Bay dolphins were 5 times more likely to have moderate–severe lung disease, generally characterized by significant alveolar interstitial syndrome, lung masses, and pulmonary consolidation. Of 29 dolphins evaluated from Barataria Bay, 48% were given a guarded or worse prognosis, and 17% were considered poor or grave, indicating that they were not expected to survive. Disease conditions in Barataria Bay dolphins were significantly greater in prevalence and severity than those in Sarasota Bay dolphins, as well as those previously reported in other wild dolphin populations. Many disease conditions observed in Barataria Bay dolphins are uncommon but consistent with petroleum hydrocarbon exposure and toxicity