This paper presents contribution s to the biology of Sebastiscus marmoratus (Cuvier et Valencinnes). The scale and otolith show similarity in mark-size, but otolith-marks are better for age-determination than scale-marks. The relationship of total length (L) to otolith-size (R) is isometric and each mark-size is standardized by L-R equation. The marks are formed in May every year The growth of this species is fitted the Putter-Bertalanffy's equation to length data, the Buch-Andresen-Fischer's equation to weight data. This ovoviviparous fish copulates in October and t h e egg-fertilization and progeny-production occur from December to February. This fish produces the progenies at several times throughout the spawning season. The number of progenies increases with age, ranging from 10,000 to 20,000 at one time.