Wild genes boost the survival of captive-bred individuals in the wild

Abstract

Captive-breeding programs are actively engaged in conservation and resource enhancement for a variety of species around the world, yet captive-bred individuals often experience reduced fitness in the wild due to inbreeding and adaptation to captivity. Increasing wild-type genetic contributions has been proposed as one solution to this problem, but the demographic impacts of these contributions remain unclear. Using data from long-term mass-marking programs conducted by national hatcheries in Japan, we evaluated the effects of wild genes in the parental generation on the survival of captive-bred populations. Our results indicated that increasing the percentage of wild genes improves survival of captive-bred offspring in the wild in two salmonid species. These findings offer insights for future bioresource management efforts that use both wild and captive-bred individuals.