Cannibalism of embryos and larvae by adult woundfin in intensive culture: Application to conservation propagation

Abstract

Woundfin Plagopterus argentissimus are a small, endangered cyprinid native to the Colorado River basin. Woundfin occur only in the Virgin River in Utah, Arizona, and Nevada, and habitat degradation and competition with invasive species threaten their survival. Three facilities raise woundfin in captivity for use in conservation propagation projects. A suspected limiting factor to pond culture production of woundfin is cannibalistic predation on embryos and larvae. We experimentally measured rates of predation on embryos and larvae by adult woundfin at the Bozeman Fish Technology Center in Montana. Predation was a significant source of mortality on both embryos (W = 210, P < 0.001) and larvae (W = 45, P = 0.004). These rates of predation could translate into the loss of thousands of fish over the course of a spawning season at the conservation propagation facilities. We recommend removing embryos from spawning ponds and rearing them in separate tanks or ponds to reduce predation loss.