Acta Ichthyologica et Piscatoria 31(1): 113-122, doi: 10.3750/AIP2001.31.1.07
Oocyte growth in freshwater catfish Mystus montanus (Jerdon, 1849) (Siluriformes: Bagridae) maturing in different salinities
expand article infoA.J. Arockiaraj, T.A. Varma, M.A. Haniffa
Open Access
Profiles of oocyte growth were obtained from female freshwater catfish Mystus montanus held in salinity ranging from freshwater (0 ‰ salinity) to sea water (35 ‰ salinity) during two consecutive spawning seasons (1999) of south-west monsoon (June-August) and north-east monsoon (October-December). Females underwent vitellogenesis at all salinities 0, 5, 10, 15, 20, 25, 30 and 35‰) tested. Females maturing in 0 ‰ (freshwater salinity content) and 15‰ (brackish water salinity content) exhibited a slower rate of oocyte growth and a significantly lower incidence of completed vitellogenesis. The test individuals died in the salinity values of 20, 25, 30, and 35‰. The other test individuals were induced to spawn at different salinities (0-15‰). The number of fertilized eggs per spawning was the highest from females maturing in 5‰ and followed by 10‰. More females were able to spawn twice (two monsoon periods) in 5 and 10‰ salinities than 0 and 15‰ salinities. The present results suggest that increasing the salinity values from 0 to 10‰ in freshwater are adequate for ovarian maturation in freshwater catfish Mystus montanus females.