Hematologic and serum biochemical reference intervals for free-ranging common bottlenose dolphins (Tursiops truncatus) and variation in the distributions of clinicopathologic values related to geographic sampling site

Objective: To develop robust reference intervals for hematology and clinical blood chemistry (HCBC) values based on a large sample from free-ranging bottlenose dolphins (Tursiops truncatus) and to examine potential variation related to geographic sampling site. Sample Population: 255 free-ranging bottlenose dolphins sampled between 2000-2006 from the southeast U.S. coast during health assessment studies in 4 geographic sites. Procedures: Data from multiple bottlenose dolphin capture-release projects were combined to determine reference intervals for 52 HCBC variables. A nonparametric bootstrap approach was applied to estimate 95th percentiles and associated 90% confidence intervals, and the need for partitioning by length and sex classes was determined by testing for differences in estimated thresholds using a bootstrap method. When appropriate, quantile regression was used to determine continuous functions for 95th percentiles dependent on length. The proportion of out-of-range samples for all HCBC measurements was examined for each geographic site and multivariate analysis of variance was applied to further explore variation in leukocyte subgroups. Results: A need for partitioning by length and sex class was indicated for many HCBC variables. There were few significant deviations from expected number of out-of-range samples for each geographic site. While mean leukocyte counts did not vary across sites, differences were indicated in the mean counts for leukocyte differentials. Conclusions: While differences were noted in the centrality of distributions for some parameters, the 95th percentiles estimated from the pooled data were robust and applicable across geographic sites. Reference intervals presented here provide critical information for conducting bottlenose dolphin population health studies.