Gonadal Histology and Spawning Season of <i>Otolithoides pama</i> in the Thanlwin River Estuary

ABSTRACT The spawning season of Otolithoides pama in the Thanlwin estuary was estimated through gonadosomatic index (GSI) and histological analyses of gonadal development. A total of 290 specimens (240 females and 50 males) were collected monthly from 5 sites—Ahlat, Kyauk Tan, Daye, Nyaung Pin Seik and Tarana—between January and December 2024. The developmental characteristics of the testes were analysed; however, they were not included in the maturity analysis. Based on the monthly GSI, the peak of GSI index occurred during the pre‐monsoon season (March–May), with spawning activity intensifying during the monsoon season (June–September), followed by a post‐spawning recovery phase. Histological analysis stated that spawning activity occurs mainly during the monsoon season, followed by a post‐spawning recovery period in the post‐monsoon months. In addition, the presence of asynchronous oocyte development was observed, indicating multiple spawning events.