Fish spawning strategies can be developed by taking into account the activity of pituitary gland gonadotropin secretion during gonad maturation. The goal of the current work was to studythe immunocytochemistry of M. cephalus gonadotrophs during ovary development in natural habitat, utilizing an antibody raised against the Coho salmon gonadotropin II (GTHII) ß subunit. The cycle of oocyte development typically go through six stages: previtellogenic primary oocytes, oocytes at the beginning of yolk vesicles deposition, and the three yolky oocytes; primary, secondary, and tertiary yolk oocytes. In addition, the ripe oocytes were observed by hormonal induction. Based on the seasonal variations observed in the histology and gonadosomatic index, five phases were identified during ovaries maturation, namely peri-vitellogenic ovary, early-, mid-, and late-vitellogenic ovaries, and prespawning ovary. Furthermore, the ripe ovary was experimentally obtained by hormonal stimulation in saline water. The gonadotropin-secreting (GTH) cells made up the larger part of the proximal pars distalis (PPD). The anti-chum salmon GTH IIß subunit exhibited a strong and specific binding to the many secretory granules found in these cells. The size, number and intensity of immunoreactive granules of GTH cells represented certain seasonal changes, occurring concurrently with ovarian development. As the ovary developed and reached reproductive maturity, the activity of of the pituitary gland to produce the gonadotropin hormone generally increased noticeably. During the development of M. cephalus ovaries, the gonadotrophs indicated a rise in the immunostaining density, granulation, size and number during ovarian maturation. Furthermore, granulation disappeared, and secretory vacuoles, along with weak immunoreaction of GTH-secreting cells, were observed during induced ripening. The spawned stage was achieved through hormonal injection