© 2020 Elsevier B.V. The demand for abalone at international level makes it a high-commercial value product, and its fishing represents an important economic activity. Several research studies have described the reproductive biology of green (Haliotis fulgens) and pink (Haliotis corrugata) abalone to determine the spawning season, but no information is still available on the effects that long-term environmental factors have on them. Considering that the environmental variables are determinant in the reproductive cycle of marine invertebrates, this study intends to evaluate the long-term spawning activity (proportion of individuals on mature, spawning and postspawning stages) of green and pink abalone; for this purpose, monthly samples of green and pink abalone in the central west coast of the Baja California peninsula were analyzed from 1982 to 2013. Generalized additive models (GAM) were used to evaluate the effects of environmental factors on the spawning activity of green and pink abalone. The results indicated that the spawning season of green abalone extends from February to August, peaking from February to April when SST ranges from 17-20 °C with prevailing winds from the northwest, and the warm phase of El Niño Southern Oscillation (ENSO) decreases spawning activity of the species. With respect to pink abalone, the results indicated that the spawning season of the species occurs from September to November when sea surface temperature (SST) is higher than 22 °C with prevailing winds from the north during strong cold and warm phases of ENSO. These results suggest that the spawning activity of both species increase/decrease in the presence of warm/cold phases of ENSO since this large-scale climate phenomenon directly modifies local environmental conditions. These findings improve the current knowledge of the reproductive biology of green and pink abalone and indicate that spawning activity of both species peaks in different seasons. Therefore, current management strategy for abalone fishery closure should be modified.