Abstract
The marine iguana (Amblyrhynchus cristata) is the world's only marine lizard and is endemic to the Galápagos Islands of Ecuador. Major threats to marine iguana populations include habitat destruction, pollution, disease, predation by feral animals, and fishing gear entanglement.1-3 Health assessments of marine iguanas may therefore have implications for wildlife biology and species conservation. Considerable research on natural history and physiology has been performed in this species, but studies on the health parameters are lacking.4-7
Reference blood parameter intervals, including hematology, biochemical, and blood gas values, have not been published for this species. Analyses were done on blood samples drawn from 35 marine iguanas captured in three locations on San Cristóbal Island. A portable blood analyzer (iSTAT) was used to obtain near immediate field results for pH, lactate, pO2, pCO2, HCO3-, Hct, Hb, Na, K, iCa, and Glu. Standard laboratory hematology techniques were employed for white cell differential counts and hematocrit determination, which was also compared to the hematocrit values generated by the iSTAT. The most notable finding was the relatively high Na levels. The iSTAT only measures to 180 mg/dl, and in many cases the Na level exceeded this value. The mean Na was 176 mg/dl. This is the highest reported blood Na level for any reptile. For hematocrit count, the iSTAT blood analyzer yielded results significantly lower than those obtained with high-speed centrifugation. Body temperature, heart rate, respiratory rate, and size/weight measurements were also recorded. The values reported in this study provide baseline data that may be useful in comparisons among populations and in detecting changes in health status among marine iguanas. The findings might also be helpful in future efforts to demonstrate associations between specific biochemical parameters and disease.
Data reported in this study represent an important step toward determining the normal range of health parameters that exist in marine iguanas. Such assessments are important for health monitoring and disease diagnostics. These results add to a growing database of knowledge about health management in wild reptiles. Future research should continue to establish reference values in this species and facilitate comparisons of blood values across age groups and geographical localities.
Acknowledgements
We thank Nicole Acostav, Diana Amoguimba, Ernesto Briones, Eduardo Espinoza, Hanne Jaasund, Tillie Laws, Carlos Mena, Philip Page, Kent Passingham, Catalina Ulloa, Carlos Valle-Castillo, Danilo Silva, Leandro Vaca, Karla Vasco, Stephen Walsh, Ecofondo Foundation-Ecuador, and the Heska Corporation for their support and assistance with this project.
* Presenting author
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