Risk Factors for Colonization of E. coli in Atlantic Bottlenose Dolphins (Tursiops truncatus) in the Indian River Lagoon, Florida

Opportunistic pathogens related to degradation in water quality are of concern to both wildlife and public health. The objective of this study was to identify spatial, temporal, and environmental risk factors for E. coli colonization among Atlantic bottlenose dolphins (Tursiops truncatus) inhabiting the Indian River Lagoon (IRL), FL between 2003 and 2007. Age, gender, capture location, coastal human population density, proximity of sewage treatment plants, number of septic tanks, cumulative precipitation 48 hrs and 30 days prior to capture, salinity, and water temperature were analyzed as potential risk factors. Highest E. coli colonization rates occurred in the northern segments of the IRL. The risk of E. coli colonization was the highest among the youngest individuals, in counties with the highest cumulative rainfall 48 hrs and in counties with the highest number of septic systems during the year of capture. The prevalence of colonization was the highest during 2004, a year during which multiple hurricanes hit the coast of Florida. Septic tanks, in combination with weather-related events suggest a possible pathway for introduction of fecal coliforms into estuarine ecosystems. The ability of E. coli and related bacteria to act as primary pathogens or cause opportunistic infections adds importance of these findings

An expert-based system to predict population survival rate from health data

This work was supported by the Office of Naval Research Marine Mammal Biology Program [grant number N00014-17-1-2868].Timely detection and understanding of causes for population decline are essential for effective wildlife management and conservation. Assessing trends in population size has been the standard approach but we propose that monitoring population health could prove more effective. We collated data from seven bottlenose dolphin (Tursiops truncatus) populations in southeastern U.S. to develop the Veterinary Expert System for Outcome Prediction (VESOP), which estimates survival probability using a suite of health measures identified by experts as indices for inflammatory, metabolic, pulmonary, and neuroendocrine systems. VESOP was implemented using logistic regression within a Bayesian analysis framework, and parameters were fit using records from five of the sites that had a robust stranding network and frequent photographic identification (photo-ID) surveys to document definitive survival outcomes. We also conducted capture-mark-recapture (CMR) analyses of photo-ID data to obtain separate estimates of population survival rates for comparison with VESOP survival estimates. VESOP analyses found multiple measures of health, particularly markers of inflammation, were predictive of 1- and 2-year individual survival. The highest mortality risk one year following health assessment related to low alkaline phosphatase, with an odds ratio of 10.2 (95% CI 3.41-26.8), while 2-year mortality was most influenced by elevated globulin (9.60; 95% CI 3.88-22.4); both are markers of inflammation. The VESOP model predicted population-level survival rates that correlated with estimated survival rates from CMR analyses for the same populations (1-year Pearson's r = 0.99; p = 1.52e-05, 2-year r = 0.94; p = 0.001). While our proposed approach will not detect acute mortality threats that are largely independent of animal health, such as harmful algal blooms, it is applicable for detecting chronic health conditions that increase mortality risk. Random sampling of the population is important and advancement in remote sampling methods could facilitate more random selection of subjects, obtainment of larger sample sizes, and extension of the approach to other wildlife species.Publisher PDFPeer reviewe

The ranging patterns of female bottlenose dolphins with respect to reproductive status: Testing the concept of nursery areas

Adult female bottlenose dolphins (Tursiops truncatus) form fission-fusion social networks and adjust their association patterns with respect to their reproductive status. It is commonly reported that mothers with dependent calves preferentially utilize \u27nursery areas\u27 consisting of protected, shallow water habitats. However, few studies have tested whether females adjust their ranging patterns based on their reproductive status. Using photo-identification data from the Indian River Lagoon, Florida (1997-2007), we conducted both longitudinal and cross-sectional analyses to compare the ranging patterns of adult females with calves versus females without calves. The size of females\u27 home ranges (HR) and core areas (CA) were not significantly different between reproductive states (P\u3e0.05), presumably due to a lack of directional pattern in the relative sizes of female\u27s home ranges when with a calf and without a calf. HR size varied greatly among individual females, 9.37-190.83km2 for females with a calf (x-±SE=76.50±10.20km2) versus 20.90-186.13km2 for the same females without a calf (97.00±11.50km2). CA size ranged from 0.35 to 56.75km2 for females with calves (14.62±3.60km2) and 0.39 to 49.72km2 for females without calves (20.01±3.60km2). Overlap between females\u27 ranges with calf and without calf also varied greatly among individuals (HR: 13.92-94.97%, CA: 0-93.97%). On average, females with calves continued to utilize 51.98±5.08% of their without calf HR but only 19.09±5.45% of their without calf CA. In our cross-sectional analyses, a large percentage (65.55±3.36%) of the 95% utilization distribution for females without calves was also used by females with calves across all seasons. However, overlap between the 50% utilization distributions of females with calves and females without calves was low (\u3c11%) in all seasons, especially autumn. These findings suggest that variation in ranging patterns among individual females was greater than by reproductive state. Females continued to use a large proportion of their overall range, but concentrated in different areas depending on their reproductive status. © 2013 Elsevier B.V