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

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.

NONPIGMENTED VERSUS PIGMENTED: HEALTH VARIABLES AND GENETICS OF ALBINO FLORIDA GREEN TURTLE (CHELONIA MYDAS) HATCHLINGS COMPARED WITH NORMALLY PIGMENTED HATCHLINGS FROM THE SAME CLUTCH.

At the time of hatchling emergence from a nest laid on Juno Beach, Florida, US, by a normally pigmented green turtle (Chelonia mydas), 23 albino hatchlings and 75 normally pigmented hatchlings were observed. This condition is rarely seen in sea turtles, and little is known about blood analytes and genetics of albino wildlife to date. Therefore, the objective of our study was to assess and compare morphometric measurements (mass, minimum straight carapace length, body condition index), carapacial scute anomalies, a suite of hematologic and plasma biochemical analytes, and two glucose analysis methodologies (glucometer and dry chemistry analysis) in albino (n=20) versus normally pigmented (n=24) hatchlings from this nest. Genetic analyses were completed to identify paternal contributions of hatchlings and to test Mendelian inheritance assumptions. Although morphometric measurements, scute anomalies, and leukocyte morphology were similar between albino and normally pigmented hatchlings, several differences were observed in blood analyte data: immature erythrocytes, packed cell volume, heterophil:lymphocyte ratio, and glucose concentrations (by both methodologies) were significantly higher, whereas absolute immature heterophils, absolute lymphocytes, number of erythrocyte micronuclei, sodium, and chloride were significantly lower in albino hatchlings compared with normally pigmented hatchlings. Considerations for these differences include a stress response from sampling (e.g., timing of procedures or possibly from photosensitivity or reduced visual acuity in albinos) and different osmoregulation, which may reflect physiologic variations or stress. There was a small positive bias (0.10 mmol/L) with glucose by glucometer, similar to reports in other sea turtle species and confirming its suitability for use in hatchlings. All albino hatchlings analyzed (n=10) were from the same father, but the normally pigmented hatchlings (n=24) were from two other fathers. These findings provide insight into the physiology and genetics of albinism in sea turtles.

Heat, health and hatchlings: associations of in situ nest temperatures with morphological and physiological characteristics of loggerhead sea turtle hatchlings from Florida.

Incubation temperatures, in addition to an embryo's genetic makeup, are critical in many aspects of adequate sea turtle embryonic development. The effects of high and low incubation temperatures on hatchling quality have been previously examined; however, many of these studies were conducted on relocated or laboratory-reared nests, which do not accurately reflect natural nest temperature fluctuations. To observe the impacts of varying in situ incubation temperatures on loggerhead sea turtle (Caretta caretta) hatchling morphology, various health variables and locomotor performance, temperature data loggers were deployed in 15 loggerhead nests on Juno Beach, Florida, between May and July 2018. Over the course of the study period, 10 morphological traits were measured, blood analytes and heart rate were assessed for the establishment of reference intervals and the self-righting response in seawater was evaluated. Warmer months were associated with smaller body size and higher body condition index, larger umbilical scar size, slower righting time, lower heart rates and higher packed cell volume, hemoglobin, total solids, total white blood cell count, absolute heterophils and absolute basophils. These findings provide evidence that higher in situ incubation temperatures have the potential to adversely affect hatchlings from warmer nests due to increased risk of predation from smaller body sizes, decreased physical responses and overall fitness, altered hemodynamic balance (e.g. dehydration) and potential inflammation and/or stress. With rising temperatures, we predict sea turtle hatchlings may have increasing risks of developing suboptimal physiological features affecting overall fitness and ultimately survival. These results demonstrate that rising environmental temperatures can negatively impact sea turtle hatchlings, thus representing additional stress on sea turtle populations and contributing to our understanding of potential pathophysiological effects of climate change on the delicate life-stage class of the sea turtle hatchling. This information will be useful for formulating effective future sea turtle management plans.