Comparison of Seasonal Variability in the Reproduction of Pacific Sardine (Sardinops sagax) from Baja California Sur, Mexico in the Year 1982-1992

Abstract

Reproductive seasonality and spawning of Sardinops sagax were studied from January 1982 to January 1992 at Bahia Magdalena, B.C.S. Samples were taken on board the commercial fleet. Morphometric parameters and maturity of the ovaries using histological procedures were recorded. The gonado somatic index was related to the size group and active female frequencies. Using the CalCOFI results, the spawning season was confirmed from 1950 to 1966, including the reproductive area of this species in the California Current. A seasonal reproductive cycle from December to July was described, with the maximum spawning activity during January and February. Another small spawning peak occurred between July and August. Environmental changes influenced reproductive seasonality, like the “ElNiño 82-83” event when no reproduction was recorded. Starting in that year, the summer peak declined until 1986 when it disappeared. Females with intense spawning activity were 160 to 210 mm in standard length. This group was present in all reproduction seasons. Abundance of sardine eggs showed a latitudinal distribution of spawning, with annual variations. Towards the South, a wide spawning period was identified with a consistent winter peak and, in some years, a small peak in early summer.