Effect of water salinity on ovarian maturation stages and 17 b-estradiol levels on fermale orange mud crab, scylla olivacea (HERBST, 1796) in captivity

Abstract

The present study was designed to focus on the effect of water salinity (10 ppt, 20 ppt and 30 ppt) on ovarian maturation stages and 17 β-estradiol levels on female orange mud crab, Scylla olivacea in captivity. Scylla olivacea were sampled from Setiu Wetlands, Terengganu on the East Coast of Peninsular Malaysia (5°31'23.1"N 102°55'56.1"E) from July to September 2015. Ovarian maturation stages were determined through colouration, Gonad Somatic Index (GSI), oocyte diameter and oocyte structure, all collected for analyzation at every 15 days throughout 60 days of culture period (Individual aquarium: 36cm x 22cm x 21 cm; Salinity: 10 ppt, 20 ppt, 30 ppt; Temperature: 27-29oC; Light intensity: ambient; Diet intake: Selaroides leptolepis at 10% body weight, every days, twice daily, at 0900 hrs and 1700 hrs), while the reproductive hormone levels 17 β-estradiol in the hemolymph were measured through Enzyme-Linked ImmunoSorbent Assay (ELISA). Morphologically, as the ovary develop, the colour start to change from translucent or whitish in colour and sometimes creamy to pale yellow, followed by light orange and lastly reddish orange.