Hatchery supplementation increases potential spawning stock of Rio Grande Silvery Minnow after population bottlenecks

Objective Supplementation of imperiled wild fish stocks with captively raised is a commonly used conservation tool. Programs designed to maintain or improve populations through supplementation should be evaluated determine whether they are meeting objectives. The Rio Grande Silvery Minnow Hybognathus amarus small-bodied, endangered minnow endemic the basin southwestern United States. population has been supplemented captive-reared since 2002. Our objective was measurably increases number spawning after years bottlenecks; this simplified because nearly all hatchery-released have given identifying markings. Methods We leveraged long-term sampling data set (18 years) covering species' contemporary range and single-season, high spatial coverage potential spawners increased by addition hatchery fish. Result Hatchery-reared catch rates up an order magnitude in some years. also observed that most hatchery-reared were recaptured near point release. able abundance distribution provided desired demographic boost severe bottlenecks. Conclusion Releasing may useful tool for freshwater fishes. However, there need rearing infrastructure matches life-history species sufficient postrelease monitoring evaluate effectiveness supplementation. Use beneficial improving resiliency following recruitment however, natural can greatly exceed conditions promoting restored.