Monitoring Eastern Hellbender Populations in the Susquehanna River Basin: Evidence for Population Stability and Massive Declines

Elaine Langone Center, Terrace Room

Over the course of nine consecutive field seasons, we have monitored multiple populations of the eastern hellbender (Cryptobranchus alleganiensis) in multiple tributaries of the Susquehanna River. Although once widespread throughout the river basin, this research has revealed that the eastern hellbender is now restricted to several tributaries of the West Branch watershed. Population monitoring has shown that some populations are stable and self-sustaining throughout a particular watershed, while significant population declines have taken place in other watersheds. In cooperation with Cornell University, we have determined that 40% of hellbenders in the river basin are infected with chytrid fungus (Batrachochytrium dendrobatidis), yet there is no direct evidence that chytrid is the underlying cause of observed population declines. Necropsies of hellbender carcasses collected from a decline location have revealed no indicators of morbidity or mortality, and all appeared healthy in gross dissection. To augment declining ellbender populations, we have begun a cooperative effort with zoological facilities in New York to raise hellbenders to an age (3-5 years) and size that will not be subject to predation when the salamanders are released into Susquehanna River tributaries.