An Environmental DNA Survey of Eastern Hellbender (Cryptobranchus A. alleganiensis) Populations in the Central Pennsylvania

Eastern hellbender (Cryptobranchus a. alleganiensis) is one of many amphibian species that have been experiencing population decline in recent years. Because of its secretive nature in aquatic habitats, it is difficult to grasp the distribution range at a regional scale. The conventional survey can be invasive as it often involves physical handling and alteration of micro-habitats. We used a non-invasive environmental DNA (eDNA) analysis, which is an analysis of genetic materials left in organism’s habitats, to survey the hellbender populations in the Susquehanna River Basin. We tested three hypotheses: 1) eDNA would detect previously unknown hellbender populations; 2) water samples from night collections would have higher eDNA concentrations than day samples because hellbenders are nocturnal; and 3) hellbender eDNA concentration would be higher during their breeding season (i.e., the end of August and September) than that during the non-breeding season. We conducted monthly water sampling from eight tributaries of the West Branch Susquehanna River between June and October 2014. Each tributary was sampled twice (day and night) every month. These tributaries are Penns Creek, Buffalo Creek, White Deer Creek, White Deer Hole Creek, Muncy Creek, Loyalsock Creek, Lycoming Creek, and Pine Creek, among which the latter four creeks contain known hellbender populations. The water samples were filtered and DNA was extracted. Quantitative PCR was used to not only detect but also obtain concentration of hellbender DNA in the samples. The preliminary data from the June samples suggest the presence of hellbender populations only in the tributaries previously known to contain its populations