Evaluating the Performance of Captive Breeding Techniques for Conservation Hatcheries: A Case Study of the Delta Smelt Captive Breeding Program

The delta smelt, an endangered fish species endemic to the San Francisco Bay-Delta, California, United States, was recently brought into captivity for species preservation. This study retrospectively evaluates the implementation of a genetic management plan for the captive delta smelt population. The captive genetic management plan entails tagging fish, molecular data collection, pedigree reconstruction, relatedness estimation, and recommending fish crosses annually in an effort to minimize the average coancestry in the population and limit inbreeding. We employed 12 microsatellite DNA markers to examine temporal genetic diversity in consecutive, discrete generations to determine the effects of intensive genetic management on the population and to quantify the amount of wild genetic diversity present within each captive generation. Wild fish are incorporated into the captive population each generation to minimize genetic drift, and 91% of the original founders are still represented in the F-3 generation. The average mean kinship in the third generation in captivity was 0.0035. There was no evidence of significant genetic divergence of the captive population from the wild population. The results of this study yield management insights into the practical application of genetic management plans for captive populations and conservation hatcheries, in an attempt to preserve the genetic integrity of endangered species.