Demography of the Hellbender Cryptobranchus alleganiensis in the Ozarks

Hellbenders Cryptobranchus alleganiensis were sampled by mark-recapture in four rivers: C. a. bishopi in the Spring River, Arkansas, and Eleven Point River, Missouri, and C. a. alleganiensis in the Gasconade and Big Piney rivers, Missouri. Densities ranged from 0.9-6.1 hellbenders per 100 m2, biomass from 66-418 kg per ha. Growth of hellbenders decreased linearly as a function of total length in all populations. Spring River hellbenders exhibited the greatest length-specific growth, Eleven Point River hellbenders the least. Females exhibited a greater length-specific mass than males in all populations. Fecundity was a positive linear function of female body length. The mean number of eggs produced per female was 480, 450, 429 and 365 by the Spring River, Gasconade, Big Piney and Eleven Point river females, respectively. Age-specific production of ova was also greatest by Spring River females because of greater growth and consequent larger body size. It was least by Eleven Point River females.