Distribution and genetic variability of young-of-the-year greater amberjack ( Seriola dumerili ) in the East China Sea

We examined the distribution and genetic variability of the greater amberjack Seriola dumerili in the East China Sea (ECS) from the mitochondrial DNA (mtDNA) control region of young-of-the-year (YOY) individuals, which may reflect the genetic characteristics of the spawning population. In the years 2016 and 2017, a total of 165 YOY S. dumerili were collected from two different locations in the ECS: the southern part of the ECS, and western Japanese coast. The spawning period was estimated using otolith daily increments from a total of 67 larvae and juveniles collected in the ECS. Results from size and age distribution indicated that S. dumerili spawned near the shelf break region in the southern ECS from January to April. Phylogenetic analysis based on mtDNA sequence data showed no significant genetic differentiation among samples collected from different locations, implying S. dumerili in the ECS is mainly composed of one population. S. dumerili around the Japanese coast may be originated from the southern ECS.