Augmentation programme for the endangered Ozark hellbender Cryptobranchus alleganiensis bishopi in Missouri

The Ozark hellbender Cryptobranchus alleganiensis bishopi is an endangered aquatic salamander that inhabits cold-water streams in the Ozark Highlands of Missouri and Arkansas in the USA. As a result of the drastic population declines over the past 40+ years, with a prominent shift in age structure (large, mature individuals predominate; young classes virtually absent), the Ozark Hellbender Working Group (OHWG) was established in 2001 to develop a conservation strategy for the species. The OHWG comprises representatives from state and federal agencies, Saint Louis Zoo (MO, USA), universities and interested individuals. Based on data from the Hellbender Population and Viability Assessment it was determined that without intervention, including a captive-propagation, head-start and augmentation programme, it was highly likely (>96% probability) that the species would go extinct within the next 75 years. Inter-agency collaboration has facilitated significant progress since the inception of the captive-propagation programme in 2002. The joint strategy of the world's first captive breeding of Ozark hellbenders in 2011 and subsequent captive breeding in the 2012–2015 period, together with the hatching and rearing of wild-collected eggs, means 6737 larvae/juveniles have been produced and/or reared at the Saint Louis Zoo. Since 2008, 3138 juvenile Ozark hellbenders reared at Saint Louis Zoo have been released into the wild in Missouri to augment remaining populations in four different streams (Bryant Creek, North Fork of the White River, Current River and Eleven Point River). Based on the success of the captive-propagation programme, post-release survival and dedicated individuals of various organizations the future of the Ozark hellbender is looking optimistic.