Introgression of the Florida Largemouth Bass Genome into Private Northern Largemouth Bass Populations in Mississippi and Texas

Florida strain Largemouth Bass have been stocked into many water bodies outside of their native range in an attempt to create trophy fisheries. The successful introgression of Florida Largemouth Bass genes into public reservoirs where Florida strain bass have been stocked has been variable with some populations having no introgression of Florida Largemouth Bass alleles, whereas Florida Largemouth Bass alleles now make up the majority of the alleles in other populations. However, no research has investigated the introgression of Florida Largemouth Bass genes in small private impoundments with little fishing effort or exploitation. Microsatellites were used to quantify percent pure northern strain, pure Florida strain, F₁ hybrid, and F_x (post-F₁ hybrids) hybrid Largemouth Bass in three small private impoundments with different stocking histories and very little exploitation.  Introgression rates were variable with pure northern strain Largemouth Bass making up 0-36% of each population, pure Florida strain from 5-31% of each population, F₁ hybrids from 14-16% of each population, and F_x hybrids from 20-55% of each population. Successful introgression of Florida strain Largemouth Bass genes was variable in small private impoundments with little fishing effort or exploitation, with different factors driving successful introgression in these populations.