Health assessment of free-ranging chelonians in an urban section of the Bronx River, New York

The Bronx River in Bronx, New York spans an area of significant human development and has suffered historic and ongoing industrial contamination. Turtles can serve as biomonitors for environmental contamination, and common... [ view full abstract ]

The Bronx River in Bronx, New York spans an area of significant human development and has suffered historic and ongoing industrial contamination. Turtles can serve as biomonitors for environmental contamination, and common snapping turtles (Chelydra serpentina) are a particularly useful study species due to their longevity, non-migratory habits, and omnivorous diet. This study evaluated the health of free-ranging native common snapping turtles and introduced red-eared sliders (Trachemys scripta) in a segment of the Bronx River. Turtles were trapped using hoop and basking traps between May and July 2012. A physical examination was performed, ectoparasites collected, complete blood counts and presence of hemoparasites determined, and blood plasma was analyzed for contaminants (mercury, thallium, cadmium, arsenic, lead, selenium, oxychlordane, alpha-chlordane, dieldrin, DDD, DDE, Aroclor 1260). Single combined swabs of the choana and cloaca were screened for ranaviruses, adenoviruses, herpesviruses, and Mycoplasma spp. by polymerase chain reaction (PCR). Both turtle species exhibited bioaccumulation of various environmental contaminants and had similar plasma concentration levels of these chemicals as have been reported from other freshwater chelonians living in contaminated sites. Sequencing of amplified herpesviral DNA polymerase from PCR positive turtles revealed a unique herpesvirus in each species. A Mycoplasma spp. previously isolated from emydid turtles was detected in red-eared sliders, while a unique Mycoplasma spp. was identified in common snapping turtles. No ranaviruses or adenoviruses were detected. This study provides a baseline health database to which future data can be compared, including assessment after river habitat restoration projects are undertaken. Moreover, it serves to expand the knowledge and patterns of health markers, environmental contaminants, and microorganisms of free-ranging chelonians.