Morphologic and physiologic characteristics of green sea turtle (Chelonia mydas) hatchlings in southeastern Florida, USA

Abstract

The ability of sea turtle hatchlings to survive into adulthood is related, in part, to their individual health status. Documenting a variety of health data is essential for assessing individual and population health. In this study, we report health indices for 297 green sea turtle (Chelonia mydas) hatchlings that emerged from 32 nests deposited on Juno Beach, Florida, USA in June-July, 2017. Results of physical examination, morphometrics, and infectious disease testing (chelonid alphaherpesvirus 5, ChHV5), and blood analyte reference intervals (hematology, plasma protein, glucose) are presented. Carapacial scute abnormalities were observed in 36% (108/297) of all hatchlings, including abnormal vertebral (86/297, 29%), lateral (72/297, 24%), and both vertebral and lateral (50/297, 17%) scutes. Hatchlings from nests laid in July, which was ~ 1.6 °C warmer than June, had significantly shorter incubation periods, and higher body mass, straight carapace length, body condition index, packed cell volume, and heterophil:lymphocyte ratios compared to hatchlings from nests laid in June. These results suggest that incubation temperatures are linked to hatchling developmental factors and size, nutritional and/or hydration status, and/or blood cell dynamics. Blood samples from all 297 hatchlings tested negative for ChHV5 DNA via quantitative PCR, including 86 hatchlings from the nests of 11 adult females that tested positive for ChHV5 via qPCR or serology in a separate study, lending support to the hypothesis that ChHV5 is horizontally (rather than vertically) transmitted among green turtles. Information resulting from this study represents a useful dataset for comparison to future health assessment and population monitoring studies of green turtle hatchlings in the northwestern Atlantic Ocean.

Keywords: ChHV5; Disease ecology; Fibropapillomatosis; Health assessment; Marine turtle; Reference intervals.