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

Common bottlenose dolphin (Tursiops truncatus) social structure and distribution changes following the 2008 Unusual Mortality Event in the Indian River Lagoon, Florida

In animal societies with fission-fusion dynamics, demographic disturbances can influence the social and spatial structure of the population. Within the Indian River Lagoon (IRL), Florida, common bottlenose dolphins (Tursiops truncatus) have experienced recurrent unusual mortality events (UMEs) providing an opportunity to examine postdisturbance population and social cluster restructuring. This study investigates the impact of the potentially nonepizootic 2008 UME on the IRL dolphin population. Photo-identification surveys conducted from August 2006 to May 2010 were stratified into pre- (August 2006–April 2008) and post-UME (September 2008–May 2010) time periods. Social network and spatial (univariate kernel density) analyses were limited to individuals sighted 5+ times per period (pre-UME = 183, post-UME = 134), and indicated a change from 11 to ten social clusters, although individuals did not always reassociate with pre-UME cluster associates. Despite the social and spatial disconnect between IRL proper and Mosquito Lagoon clusters, both network density and core area spatial overlap increased post-UME allowing for increased intercluster interactions. However, intracluster associations increased as well, allowing the population to maintain multiple social clusters within a loosely connected network. This study shows the important role sociality may play in the adaptability of cetaceans to environmental and demographic changes

Spatiotemporal movements of common bottlenose dolphins (Tursiops truncatus truncatus) in Northeast Florida, USA

Common bottlenose dolpliins (Tursiops inmca-tus truncatus) (hereafter referred to as dolpliins ) are distributed along the east coast of Florida in a longitudinal continuum within inland waterways and federally managed via assignment into stocks. Seven regional studies have identified local estuaiine populations with resident and seasonally transient dolpliins. However, study area boundaries limit understanding of distribution and movement patterns between these geographically separated regions. To reveal the bigger picture of spatiotemporal movements, a multi-organizational consortium conducted semiannual photo-identification surveys from the Florida-Georgia border to Titusville, Florida (331 km). The study area incorporated dolpliins occurring in the Jacksonville Estuaiine System (JES) stock in the north, the Mosquito Lagoon within the Indian River Lagoon Estuaiine System (IRLES-ML) stock in the south, and the connecting 156-km inland waterway currently managed under the Western North Atlantic Northern Florida and Central Florida coastal stocks. The area was divided into segments, and simultaneous surveys were conducted from 2011 to 2016 during two primary sampling seasons within each year: five summers and five winters (primary period), with two to three surveys (secondary sessions) within each primary period separated by one-week intervals to allow mixing of the population. A total of 6,896 dolpliins. including 196 neonates, were observed, and 649 individuals were identified. Spatial autocorrelation analyses of 222 marked dolphins sighted in \u3e 5 primary surveys revealed that 78fc exhibited significant regional and seasonal fidelity to one or more segments, which no single study could elucidate. Additionally, JES-North dolphins demonstrated strong regional site fidelity and were consistently sighted during both seasons, similar to studies in the 1990s, and continued to be partitioned from dolphins to the south. JES-Soutli and IRLES-ML dolphin home ranges extended beyond previously known boundaries. Based on spatiotem-poral movement patterns between the segments, recommendations are made to revise boundaries of the JES and IRLES stocks