Synchronization between bivalve reproductive cycles and primary productivity is fundamental for recruitment success in regions subject to seasonal upwelling. The gametogenic cycle of Leukoma asperrima was investigated using histometric indicators and physiological indices under the influence of thermal and salinity variability in the Panamanian Pacific. Analysis revealed a bimodal reproductive strategy, with a primary spawning period between October and February and a secondary event between April and June, coinciding with water cooling and increased phytoplankton density. The average annual Gonadosomatic Index (GSI) was 31.39, peaking in April (34.26). Histometrically, oocyte diameter ranged from 55.32 µm to 65.83 µm, reflecting intense vitellogenic activity prior to spawning peaks. The population was identified as dioecious, with a mean sex ratio of 1:1.2 (F:M) and no evidence of hermaphroditism. Sex determination was validated via gonadal smears, an essential technique given the absence of macroscopic chromatic dimorphism. It is concluded that temperature acts as the primary modulator of gonadal conditioning, while food availability regulates the rate of gamete maturation. This study provides novel data on the reproductive ecology of the species, essential for understanding its resilience to climate change and anthropogenic pressure.
