Genetic pattern fluctuations in wild swimming crab populations, under the influence of continuous mass stock enhancement

•This is the first result of the genetic response of the local wild population to large-scale release activities.•We monitored the temporal variations in genetic diversity and structure in two natural habitats of swimming crab across six years.•Genetic diversity indices were not stable and fluctuations, particularly apparent in the temporal Panjin populations.•This phenomenon may reflect the interactions between the crab life cycle and intensive anthropogenic manipulations.