Wild at heart: Programs to diminish negative ecological and evolutionary effects of conservation hatcheries

Abstract

Hatchery programs are critical for conservation and management of many imperiled fishes. Most traditional aquaculture programs negatively affect ecological performance, genetic, and phenotypic diversity of hatchery-origin fish compared with wild counterparts. Here, we synthesize outcomes of three conservation programs aimed at enhancing ‘wildness’. Each program focuses on a different species: lake sturgeon, razorback sucker, and Rio Grande silvery minnow. These species differ in key life history traits including size and age at sexual maturity, reproductive and migratory behavior, and habitat requirements. Threats to persistence of the focal taxa, however, exemplify common pressures experienced by freshwater fishes worldwide. Conservation hatchery programs for lake sturgeon, razorback sucker, and Rio Grande silvery minnow capitalize on natural spawning in the wild followed by collections of wild-fertilized eggs/larvae for hatchery rearing. Individuals are repatriated to the wild after rearing to body sizes less susceptible to mortality. Protocols include collections of eggs or larvae across the entire spawning period and at appropriate geographic scales to maximize retention of genetic diversity and, to increase the likelihood of preserving variation for heritable life history traits. Using direct and indirect evidence we show that hatchery programs that allow individuals to fulfill parts of the life-cycle in their native habitats can be conducted without compromising genetic diversity. Adoption of similar strategies in other imperiled fishes would improve understanding of species life history, and provide an incentive to protect native habitats so they may eventually support self-sustaining populations.