Arcuatula senhousia, a bivalve mollusk, exerts a significant negative impact on ecological aspects within the realm of bivalve aquaculture. This study delved into the reproductive cycle and distribution of A. senhousia in Jinju Bay, Korea, spanning from February to December 2020. The species inhabiting Jinju Bay displayed a dense concentration in the central part of the bay, where shellfish aquaculture facilities are prevalent. However, they experienced a complete die-off in August, and no specimens were collected thereafter until the conclusion of the experiment. The reproductive cycle of A. senhousia, collected from February to July 2020, revealed that 13.6% were females, while 56% were males in the early developmental stage among the specimens collected in February. Males exhibited a more rapid maturation of reproductive organs. Gonadal maturation was observed in both male and female specimens starting in May, with spawning occurring from May to July. The mortality of A. senhousia observed in August was attributed to underwater hypoxia or anoxic conditions. The insights into the reproductive cycle of A. senhousia inhabiting the Jinju Bay area are anticipated to hold value for the development of techniques in shellfish aquaculture management.