HEALTH ASSESSMENTS OF FEMALE DIAMONDBACK TERRAPINS (MALACLEMYS TERRAPIN) FROM TWO NESTING POPULATIONS IN JAMAICA BAY, NEW YORK CITY, USA.

Abstract

The diamondback terrapin (Malaclemys terrapin) is a unique turtle species living in brackish water, with numerous factors contributing to population declines throughout its range along the US eastern and Gulf of Mexico coasts and Bermuda. Health assessments, including clinical examination (n = 37), CBC and plasma biochemistry (n = 25), and priority chelonian pathogen testing (herpesvirus, ranavirus, adenovirus, tortoise intranuclear coccidiosis [TINC], and Mycoplasma spp.; n = 37) were performed on terrapins from two variably successful nesting populations in Jamaica Bay, an urban estuarine bay in New York City (Ruler's Bar Hassock [RBH] and John F. Kennedy International Airport [JFK]). Reference values were determined for clinicopathologic tests. The terrapins from the growing population at JFK had significantly higher magnesium, blood urea nitrogen, and γ-glutamyl transferase, as well as lower eosinophils, prealbumin, and albumin, than those from the declining RBH population. Although increased magnesium may support normal egg production and eosinophilia may support parasitic infection, no other clinicopathologic differences between the populations are considered likely to be correlated with reproductive success. No systemic physical examination abnormalities or hemoparasites were identified. All individuals were negative for herpesvirus, ranavirus, and TINC. Diamondback terrapins in New York City have a high prevalence of a novel Mycoplasma sp. (86% of samples tested were positive). A novel adenovirus was also identified with 19% prevalence. Diamondback terrapins that were positive for this novel Mycoplasma sp. or adenovirus exhibited no clinical signs, physical examination abnormalities, or clinicopathologic alterations. These findings support the growing body of evidence that some species of Mycoplasma and adenoviruses may be asymptomatically harbored by some chelonian species, though their importance to ecosystem health or potential pathogenicity to other chelonians warrants further studies and monitoring.