Long distance dispersal with kinship in the Yangtze River during early life stage of a freshwater fish

Abstract

Aggregation is suggested beneficial with foraging, defense, and other fitness for the group members. While long distance dispersal with kinship has been found in several marine fishes, similar cases have not been reported in inland waters. We utilized microsatellite genotype data of 397 eggs or juvenile silver carp (Hypophthalmichthys molitrix) born in 2017 from the middle and lower reaches of the Yangtze River in China to analyze their relatedness and infer the dispersal patterns during their early life stages and whether they dispersed with their kinship. There were 11–58 pairs of full siblings or half siblings between samples from the spawning ground (Yichang section) and other sites (34.1–1047.2 ​km) which showed the dispersal path. Particularly, the proportion of maternal siblings (mean: 47.9%) was higher than random, indicating kinship aggregation, or that the fish traveled with their kinship during their early life stages. Such kin aggregation has profound implications for our understanding of early life stage dispersal in inland water fish populations. Our findings suggest that the preservation of habitats along the middle Yangtze River should be increased. In particular, the channelized river bank should be rebuilt with more heterogeneous habitat, and the lake-river connections should be restored to expand the amount of appropriate habitat.