Genetic Pedigree Reconstruction Facilitates Lakewide Estimates of Age-0 Largemouth Bass Dispersal

Dispersal from natal areas is an important event for fishes, ultimately affecting individual adult reproductive success and population levels of recruitment and genetic diversity. However, quantification of dispersal rates and distance and the associated environmental covariates is difficult when individuals are too small to physically mark. Using genetic techniques, we studied the dispersal of largemouth bass Micropterus salmoides from their natal nests in two southern Michigan lakes. In Warner Lake, we sampled larvae from 33 nests during spring 2010 and collected 33 age-0 fish during summer. In Lake Chemung, we collected 138 and 140 age-0 fish during the summers of 2009 and 2010, respectively. Pedigree reconstruction techniques were used to determine (1) the dispersal distance of age-0 largemouth bass from nests to late-summer points of capture (Warner Lake) and (2) interindividual distances between age-0 full-sibling pairs (Lake Chemung). Age-0 fish in Warner Lake dispersed an average of 301 +/- 41 m (mean +/- SE). In Lake Chemung, intersibling dispersion distances varied substantially among pairs, but the distribution of distances was not significantly different from that of randomly selected pairs of individuals. Together, the data showed that age-0 largemouth bass dispersed considerable distances from their nests and that the distance and direction of dispersal by siblings appeared to be independent of nest site. Our methods can be widely used for detailed evaluation of fish dispersal and effects of physical and biotic lakescape features on dispersal and recruitment.