Specimens of Bathygobius soporator (Gobiidae) were obtained from the Lagos lagoon, aspects of the biology studied were length-weight relationships, feeding habits and gonadosomatic index (GS1). The sizes ranged between 101 and 190mm (mean TL = 147.1) and 10.5 and 88.2g for the body weight (mean BW= 46.3) respectively. The von Bertalanffy growth parameter of the specie indicated length at infinity, L„ =200mm; growth coefficient, K= -0.398; age at length zero, to =0.445 year; and the length at maturity. =190mm, its mean condition factor; K (1.43 x 10- 3) for males, and (1.28 x 10-3) for the females. The diets of the fish consist mostly: worms (90.87%), Penaeus notialis (6.94%), and tilapia sp (2.18%) in % composition by number 66.67%, 35.56%„ and 17.77% for frequency of occurrence respectively. Five stages of maturity were established according to Simpson.. (1951): immature, resting, developing ripening, reproductive and gravid stage. Specimens at their ripening stage were most abundant. Sex ratio of male to female is 1: 0.4, and the fecundity was between 1.2 x 104 and 6.8 x 104 for 125mm (28.1g fish) and 182mm (52.2g fish) respectively. The mean GSI was 0.51% for males and 5.15% for females.
