Blood Parameters From a Population of Clinically Healthy Galapagos Green Turtles (Chelonia mydas)
The green turtle (Chelonia mydas), also known as the black turtle in the Pacific Ocean, is a marine chelonian inhabiting oceans throughout the world.17 The green turtle is currently listed as Endangered on the IUCN Red List, and no commercial use is permitted under CITES Appendix I. Major threats to green turtle populations include habitat destruction, pollution, disease, consumption of meat and eggs by local populations, fishing gear entanglement, and consumption of plastics and other anthropogenic materials.5,12,15-17 Health assessments of green turtles may therefore have implications for wildlife biology and species conservation. Considerable research on natural history has been performed in this species and studies on the health parameters of green turtles, while still relatively limited, have increased dramatically in the last 5 years.1-4,6,7,9-11,13,14 A recent review summarizes the health of wild sea turtles and methods of assessment, including blood parameters.8
Reference blood parameter intervals have been published for certain chelonian species, including sea turtles, but baseline hematology, biochemical, and blood gas values are lacking from the Galapagos sea turtles. Blood gases, biochemical parameters, and hematology were evaluated in 28 green turtles captured in two foraging locations on San Cristóbal Island (14 from each site). Of these turtles, 20 were immature and of unknown sex; the other eight were males (five mature, three immature). A portable blood analyzer (iSTAT) was used to obtain near immediate field results for pH, lactate, pO2, pCO2, BEecf, HCO3-, Hct, Hb, Na, K, iCa, and Glu. Parameter values affected by temperature were corrected with standard formulas, and were compared with the iSTAT's internal corrected numbers. Standard laboratory hematology techniques were employed for the red and white blood cell counts and resulting hematocrit was compared to the values generated by the iSTAT. Of all blood analytes, only lactate concentrations were positively correlated with body size. All other values showed no significant difference between the two sample locations nor were they correlated to body size or internal temperature. The iSTAT blood analyzer provided reliable results for hematocrit counts as well as for temperature-corrected pH and pCO2, compared to the manually obtained values. In contrast, results for HCO3-and pO2 differed significantly between the manual and iSTAT calculations.
Data from this study represent a reference against which future blood gas and biochemistry results in green turtles may be compared, and also demonstrate associations between certain biochemical parameters, size, and health status. All 28 turtles were judged to be clinically healthy and their blood parameters support this assessment. Because green turtles are an endangered species with importance in the wildlife biology research community and the aquarium/zoo industry, health assessments are important from the standpoint of sustainable conservation and management. These results add to a growing database of knowledge about health management in wild chelonian species. Future research should continue to establish reference values in this species and facilitate comparisons of blood values across age groups and disease states.
We thank Diana Amoguimba, Eduardo Espinoza, Craig Harms, Tillie Laws, Carlos Mena, Philip Page, Kent Passingham, Carlos Valle-Castillo, Galo Quezada and Stephen Walsh for their support and assistance with this project.
* Presenting author
1. Aguirre AA, Balazs GH, Spraker TR, Gross TS. Adrenal and hematological responses to stress in juvenile green turtles (Chelonia mydas) with and without fibropapillomas. Physiol Zool. 1995;68(5):831–854.
2. Anderson NL, Wack RF, Hatcher R, Wack F. Hematology and clinical chemistry reference ranges for clinically normal, captive New Guinea Snapping Turtles (Elseya novaeguineae) and the effects of temperature, sex, and sample type. J Zoo Wildl Med. 1997;28:394–403.
3. Anderson ET, Harms CA, Stringer EM, Cluse WM. Evaluation of hematology and serum biochemistry of cold-stunned green sea turtles (Chelonia mydas) in North Carolina, USA. J Zoo Wild Med. 2011;42(2):247–255.
4. Bolton AB, Bjorndal KA. Blood profiles for a wild population of green turtles (Chelonia mydas) in the Southern Bahamas: size-specific and sex-specific relationships. J Wild Dis. 1992;28(3):407–413.
5. Deem SL, Norton TM, Mitchell M, Segars A, Alleman AR, Cray C, Poppenga RH, Dodd M, Karesh WB. Comparison of blood values in foraging, nesting, and stranded loggerhead turtles (Caretta caretta) along the coast of Georgia, USA. J Wild Dis. 2009;45:41–56.
6. Flint M, Morton JM, Limpus CJ, Patterson-Kane JC, Murray PJ, Mills PC. Development and application of biochemical and haematological reference intervals to identify unhealthy green sea turtles (Chelonia mydas). Vet J. 2010;185:299–304.
7. Flint M, Patterson-Kane JC, Limpus CJ, Murray PJ, Mills PC. Health surveillance of stranded green turtles in Southern Queensland, Australia (2006–2009): an epidemiological analysis of causes of disease and mortality. EcoHealth. 2010b;7:135–145.
8. Flint M. Free ranging sea turtle health. In: Wyneken J, Lohmann KJ, Musick JA, eds. The Biology of Sea Turtles, Vol. III. Boca Raton, FL: CRC Press, Inc.; 2013: 379–397.
9. Fong CL, Chen HC, Cheng IJ. Blood profiles from wild populations of green sea turtles in Taiwan. J Vet Med Anim Health. 2010;2(2):8–10.
10. Hamann M, Schäuble CS, Simon T, Evans S. Demographic and health parameters of green sea turtles Chelonia mydas foraging in the Gulf of Carpentaria, Australia. Endang Spec Res. 2006;2:81–88.
11. Harms CA, Eckert SA, Jones TT, Dow Piniak WE, Mann DA. A technique for underwater anesthesia compared with manual restraint of sea turtles undergoing auditory evoked potential measurements. J Herp Med Surg. 2009;19(1):8–12.
12. Koch V, Nichols WJ, Peckham H, De La Toba V. Estimates of sea turtle mortality from poaching and bycatch in Bahia Magalena, Baja California Sur, Mexico. Biol Conserv. 2006;128:327–334.
13. Labrada-Martagón V, Méndez-Rodriguez LC, Gardner SC, López-Castro M, Zenteno-Savin T. Health indices of the green turtle (Chelonia mydas) along the Pacific coast of Baja California Sur, Mexico. I. Blood biochemistry values. Chelonian Conserv Biol. 2010a;9(2):162–172.
14. Labrada-Martagón V, Méndez-Rodriguez LC, Gardner SC, Cruz-Escalona VH, Zenteno-Savin T. Health indices of the green turtle (Chelonia mydas) along the Pacific coast of Baja California Sur, Mexico. II. Body condition index. Chelonian Conserv Biol. 2010b;9(2):173–183.
15. Mancini A, Koch V, Seminoff JA, Madon B. Small-scale gill-net fisheries cause massive green turtle Chelonia mydas mortality in Baja California Sur, Mexico. Oryx. 2012;46(1):69–77.
16. Parra M, Deem SL, Espinoza E. Green turtle (Chelonia mydas) mortality in the Galapagos Islands, Ecuador during the 2009–2010 nesting season. Marine Turtle Newsletter. 2011;130:10–15.
17. Wyneken J, Lohmann KJ, Musick JA, eds. The Biology of Sea Turtles, Vol. III. Boca Raton, FL: CRC Press, Inc.; 2013: 379–397.