Metabolite compositions on skins of eastern hellbenders Cryptobranchus alleganiensis alleganiensis differ with location and captivity.

Eastern hellbenders Cryptobranchus alleganiensis alleganiensis, large aquatic salamanders, are declining over most of their range. The amphibian-killing fungus Batrachochytrium dendrobatidis (Bd) has contributed to global amphibian declines and has been detected on eastern hellbenders, but infection intensities were lower than those of species that are more susceptible to Bd. The factors limiting Bd on hellbenders may include antifungal metabolites produced by their skin microbiota. We used a metabolite fingerprinting technique to noninvasively identify the presence, but not identity, of metabolites associated with eastern hellbenders. We surveyed the skin of wild eastern hellbenders to test whether the composition and richness (i.e. number of metabolites) of their metabolites are explained by Bd status or location. Furthermore, we surveyed for metabolites on captive eastern hellbenders to test whether metabolite compositions were different between captive and wild eastern hellbenders. Bd detection was not associated with either metabolite richness or composition. Both metabolite composition and richness differed significantly on hellbenders from different locations (i.e. states). For metabolite composition, there was a statistical interaction between location and Bd status. Metabolite richness was greater on captive eastern hellbenders compared to wild hellbenders, and metabolite compositions differed between wild and captive eastern hellbenders. The methods we employed to detect metabolite profiles effectively grouped individuals by location even though metabolite composition and richness have high levels of intraspecific variation. Understanding the drivers and functional consequences of assemblages of skin metabolites on amphibian health will be an important step toward understanding the mechanisms that result in disease vulnerability.

Pathogenic chytrid fungus Batrachochytrium dendrobatidis, but not B. salamandrivorans, detected on eastern hellbenders.

Recent worldwide declines and extinctions of amphibian populations have been attributed to chytridiomycosis, a disease caused by the pathogenic fungus Batrachochytrium dendrobatidis (Bd). Until recently, Bd was thought to be the only Batrachochytrium species that infects amphibians; however a newly described species, Batrachochytrium salamandrivorans (Bs), is linked to die-offs in European fire salamanders (Salamandra salamandra). Little is known about the distribution, host range, or origin of Bs. In this study, we surveyed populations of an aquatic salamander that is declining in the United States, the eastern hellbender (Cryptobranchus alleganiensis alleganiensis), for the presence of Bs and Bd. Skin swabs were collected from a total of 91 individuals in New York, Pennsylvania, Ohio, and Virginia, and tested for both pathogens using duplex qPCR. Bs was not detected in any samples, suggesting it was not present in these hellbender populations (0% prevalence, 95% confidence intervals of 0.0-0.04). Bd was found on 22 hellbenders (24% prevalence, 95% confidence intervals of 0.16 ≤ 0.24 ≤ 0.34), representing all four states. All positive samples had low loads of Bd zoospores (12.7 ± 4.9 S.E.M. genome equivalents) compared to other Bd susceptible species. More research is needed to determine the impact of Batrachochytrium infection on hellbender fitness and population viability. In particular, understanding how hellbenders limit Bd infection intensity in an aquatic environment may yield important insights for amphibian conservation. This study is among the first to evaluate the distribution of Bs in the United States, and is consistent with another, which failed to detect Bs in the U.S. Knowledge about the distribution, host-range, and origin of Bs may help control the spread of this pathogen, especially to regions of high salamander diversity, such as the eastern United States.

Occurrence of perfluoroalkyl surfactants in water, fish, and birds from New York State.

Concentrations of perfluorooctanesulfonate (PFOS) and several other perfluoroalkyl surfactants (PASs) were determined in nine major water bodies (n = 51) of New York State (NYS). These PASs were also measured in the livers of two species of sport fish (n = 66) from 20 inland lakes in NYS. Finally, perfluorinated compounds were measured in the livers of 10 species of waterfowl (n = 87) from the Niagara River region in NYS. PFOS, perfluorooctanoic acid (PFOA), and perfluorohexanesulfonate (PFHS) were ubiquitous in NYS waters. PFOA was typically found at higher concentrations than were PFOS and PFHS. Elevated concentrations of PFOS were found in surface waters of Lake Onondaga, and elevated concentrations of PFOA were found in the Hudson River. PFOS was the most abundant perfluorinated compound in all fish and bird samples. PFOS concentrations in the livers of fishes ranged from 9 to 315 ng/g wet weight. PFOS, PFOA, and PFOSA (perfluorooctanesulfonamide) concentrations in smallmouth and largemouth bass (taken together) caught in remote mountain lakes with no known point sources of PAS contamination were 14 to 207, < 1.5 to 6.1, and < 1.5 to 9.8 ng/g wet weight, respectively. PFOS concentrations in the livers of birds ranged from 11 to 882 ng/g wet weight. PFOS concentrations were 2.5-fold greater (p = 0.001) in piscivorous birds than in non-piscivorous birds. However, PFOA, PFOSA, and PFHS were not found in bird livers. Overall, average concentrations of PFOS in fish were 8850-fold greater than those in surface water. An average biomagnification factor of 8.9 was estimated for PFOS in common merganser relative to that in fish. This study highlights the significance of dietary fish in PFOS accumulation in the food chain. Furthermore, our results provide information on the distribution of PASs in natural waters, fish, and several bird species in NYS.