Reproduction of Selar crumenophthalmus of the Pacific coast, Mexico was studied. Fish were captured with fixed trap-net, gill net, “robador” (hand line with five hooks) and pound net. This species is used exclusively as bait in Colima to catch big pelagic fish with long line and sport fishing of sail fish, marlin and dolphin fish. The proportion of male: female was 1: 0.73. Average length of sexual maturity (L50) was 20.80 cm in males and 20.55 in females; average length of first maturity L25 = 20.00 cm for both sexes. The allometric relationship between liver weight and fish length is isometric (b = 2.965). Maximum values were observed in January, July, August, October and November. The gonadosomatic index (GSI) reached its highest values during F ebruary-April, and August-November. The gastric repletion index showed higher values during March, April, July and October, the lower values were observed during February, August and September. Higher values of the condition factor were obtained in February-April, September and October with the indexes of Fulton, Clark and Safran. Oocyte diameter was 0.28 mm (±0.02 mm standard deviation: SD), minimum 0.24 mm and maximum 0.30 mm. Fecundity values ranged from 86,760 to 245,114 oocytes in females of two to six years of age and lengths of 19.04 cm to 24.21 cm, and 68.37 g to 148.49g of weight. Average value of relative fecundity was of 1,667.3 oocytes·g-1 (ranging from 70.4 to 4,609.4 oocytes·g-1).
