Genetic Diversity among Hatchery Stocks and Established Populations of Rainbow Trout in Missouri

Abstract

AbstractIntroduction of rainbow trout Oncorhynchus mykiss in Missouri over the last 125 years has established numerous self‐sustaining populations. While many populations have been repeatedly stocked, some have received few fish beyond the original releases, and it is possible that those populations currently represent their source lineages. There is angler interest in fishing “wild” rainbow trout populations both for historical purposes and for the fighting ability of hooked fish. A genetic inventory was conducted to determine the extent to which Missouri's wild fish differ from hatchery stocks. Haplotype diversity in the mitochondrial DNA (mtDNA) cytochrome b gene and allele frequencies at four microsatellite loci were examined. Significant differences in mtDNA genotypes were found among several wild and hatchery sources, indicating that multiple sources of rainbow trout were probably represented. Crane Creek—long considered a stronghold of McCloud River (California) redband trout O. mykiss stonei in Missouri—and its tributary, Spring Creek, were characterized as having a large proportion of unique haplotypes. Microsatellite diversity was largely shared among individuals within populations, and average heterozygosity was high. By including this information in decisions about regulations and stocking, the Missouri Department of Conservation can manage rainbow trout to satisfy angler interests with respect to both historical and performance‐related population characteristics.