Endangered species augmentation: a case study of alternative rearing methods


post-stocking survival, semi-natural rearing, Chasmistes liorus


Stocking of artificially propagated fish has been adopted by many endangered fish recovery programs as a key component of their recovery plans. However, quantifying successful recruitment of individuals to the adult population is difficult, especially in long-lived species. To evaluate the effect of the rearing environment on recruitment in the native environment, we compared post-stocking survival of the endangered June sucker Chasmistes liorus reared under conventional hatchery practices to those reared in 2 reservoirs. We used logistic regression analysis to compare patterns of survival among populations including total length and condition at the time of stocking as continuous covariates. The estimated probability of survival for reservoir-reared fish from Red Butte and Camp Creek Reservoirs was 0.19 and 0.05, respectively, compared to 0.05 for hatchery-reared fish. Length and condition were positively related to post-stocking survival. On average, reservoir-reared fish performed better than hatchery-reared fish. It is not clear what mechanism led to increased survival for the Red Butte source, but several studies have demonstrated the importance of acclimation to the physical environment and the threat of predation. We suggest that augmentation procedures would produce more recruits to the adult population if they incorporate grow-out or at least acclimation in more natural environments than that provided by hatcheries prior to release in Utah Lake.

Original Publication Citation

Rasmussen, J.E., M.C. Belk, and S.L. Peck. 2009. Endangered species augmentation: a case study of alternative rearing methods. Endangered Species Research 8:225-232.

Document Type

Peer-Reviewed Article

Publication Date


Permanent URL



Endangered Species Research




Life Sciences



University Standing at Time of Publication

Full Professor