Growth and gonad development of captive chub mackerel Scomber japonicus (Perciformes: Scombridae)

• Published in: Aquaculture Science Vol. 54; no. 2; pp. 195 - 200
• Main Authors: Ishibashi, R.(Kinki Univ., Shirahama, Wakayama (Japan). Fisheries Lab.), Murata, O, Yamamoto, S, Oka, Y, Yoneshima, H, Kato, K, Miyashita, S, Kumai, H
• Format: Journal Article
• Language: Japanese; English
• Published: Japanese Society for Aquaculture Science 20.06.2006
• Subjects: BODY MEASUREMENTS; CAGE CULTURE; Captive experiment; CULTIVO EN JAULAS; CULTURE EN CAGE; GAIN DE POIDS; GANANCIA DE PESO; GENITALIA; Gonad somatic index; Growth; MADUREZ SEXUAL; MATURITE SEXUELLE; MEDICION DEL CUERPO; MENSURATION CORPORELLE; OVIPOSICION; OVIPOSITION; PONTE; SCOMBER JAPONICUS; SEXUAL MATURITY; WEIGHT GAIN
• ISSN: 0371-4217; 2185-0194
• DOI: 10.11233/aquaculturesci1953.54.195

Growth, and seasonal changes in the gonadosomatic index (GSI) and KG values were investigated in captive chub mackerel, Scomber japonicus, kept at the Fisheries Laboratory, Shirahama Experimental Station, Kinki University. Mean monthly water temperatures ranged between 12.6 and 29.3 deg C. At the start of the experiment, the mean fork length and body weight of 30-days-old hatchings were 10.5 +- 0.8 cm and 11.0 +- 2.9 g, respectively; while at the end of the two year experiment, these fish measured 33.0 +- 0.8 cm and 353.0 +- 50.0 g, respectively. In one-year old fish, GSI and female KG values increased during February and June. In two-year old fish, GSI and female KG values increased in January. The GSI and KG values were high on average between March and July, with the highest GSI and KG values being 14.9, and 10.3, respectively. In April all males had mature spermatozoa and some females had mature eggs. The results suggested that males and females matured at one and two years, respectively, after hatching.