Comprehensive health assessment of green turtles Chelonia mydas nesting in southeastern Florida, USA

A Page-Karjian,Cr Gregory,S Stewart,Lh Herbst,Ra Valverde,Bw Ritchie,Cm Coppenrath,As Morgan,R Chabot,Ni Stacy,Ca Manire,Jr Perrault

doi:10.3354/esr01036

Abstract

Important indicators of population health needed for large-scale sea turtle population recovery efforts include demographics, disease and mortality trends, condition indices, and baseline blood data. With this comprehensive health assessment of adult female green sea turtles Chelonia mydas nesting on Juno Beach, Florida, USA, we (1) established comprehensive baseline health indices; (2) identified individuals with evidence of infection by chelonid alphaherpesviruses 5 and 6 (ChHV5, ChHV6), which are implicated in fibropapillomatosis and respiratory and skin disease, respectively; and (3) compared measured health indices between turtles that did versus those that did not test positive for ChHV5 and/or ChHV6. All 60 turtles included in the study were in good body condition with no external fibropapillomatosis tumors. Hematological and biochemical reference intervals were established. Via quantitative PCR (qPCR), 5/60 turtles (8%) tested positive for ChHV5, and all turtles were negative for ChHV6. Of 41 turtles tested for antibodies to ChHV5 and ChHV6, 29% and 15% tested positive, respectively, and 10% tested positive for antibodies to both viruses. Notably, there were no statistically significant differences between health variables for nesting turtles that tested positive for ChHV5 DNA versus those that tested negative; and also no differences between turtles that tested positive for ChHV5 or ChHV6 antibodies and those that did not. This suggests that these viruses are enzootically stable in Florida’s adult green turtles. This study provides a health profile of nesting green turtles in southeastern Florida applicable to temporal and spatial investigations of this and other populations.

Highlights

Green turtles Chelonia mydas are the second most common sea turtle species to nest on the coast of Florida, USA, after loggerhead turtles Caretta caretta (FWC 2018a)
The objective of this study was to conduct a health assessment of adult female green turtles nesting on Juno Beach in order to (1) establish comprehensive baseline health indices, including physical examination findings, hematology, and plasma biochemistry values; (2) evaluate whole blood and plasma samples to identify individuals infected with enzootic herpesviruses (ChHV5, chelonid alphaherpesvirus 6 (ChHV6)); and (3) compare the measured health indices between the turtles that did versus those that did not test positive for either chelonid alphaherpesvirus 5 (ChHV5) or ChHV6, to identify any blood biomarkers that may be associated with subclinical infection
Blood samples were collected from 60 green turtles that nested on Juno Beach during 2017; assuming that each individual turtle nests ~5−8 times (Esteban et al 2017), these 60 turtles represent ~7−11% of all green turtles that nested on Juno Beach in 2017

Summary

Introduction

Green turtles Chelonia mydas are the second most common sea turtle species to nest on the coast of Florida, USA, after loggerhead turtles Caretta caretta (FWC 2018a). Establishing cohort-specific baseline health data within a population is a valuable tool for assessing the overall health of a population, for use as a baseline in longitudinal monitoring efforts, and for use as prognostic indicators in individual health assessments and patient care of stranded turtles (Deem et al 2009). Such baseline health assessments of a sea turtle population can provide useful science-based information for wildlife and environmental policy management

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