LAUSR

Abstract This study determined the effect of water salinity on the level of 17β-estradiol and the ovarian physiology (histological changes) of Scylla olivacea in captivity. Sixty newly mature crabs with immature ovaries (carapace width > 90.0 mm, Stage 1 ovary) were exposed to three salinity levels (10, 20 and 30 ppt) for 60 days. The level of 17β-estradiol peaked in the early days of each treatment for all salinity levels but decreased as the crabs matured. Stage 4 ovaries were most produced in the 20 ppt treatment, followed by the 10 ppt treatment, and then the 30 ppt treatment. No significant difference was found for the level of 17β-estradiol between salinity levels, but the oocyte size was observed to be significantly different between salinity levels. Meanwhile, there was a significant negative correlation between oocyte diameter size and the 17β-estradiol level. The study concludes that salinity can affect ovarian maturation but not 17β-estradiol levels.