海洋科学: 研究開発

抽象的な

Reproductive Biology of the Commercially Important Portunid Crab, Portunus sanguinolentus (Herbst)

Soundarapandian P, Varadharajan D and Boopathi A

The male reproductive system of P. sanguinolentus is bilaterally symmetrical creamy to whitish in colour, composed of a pair of testes, a pair of vas differentia, and a pair of ejaculatory ducts internally, and a pair of pleopods externally as accessory reproductive organs, present on the inner side of the abdominal flab. The vas differentia has been divided into three distinct regions, based on the morphological and functional criteria: Anterior (AVD), Median (MVD) and Posterior (PVD) vas deferens. The gonads of the male measuring below 8.5 cm carapace width (CW) has immature stage, above 10.5 cm CW has mature stage, whereas the CW in between 14.5-10.5 cm was maturing stage. The female reproductive system composed of a pair of ovaries, a pair of seminal receptacles (or) spermatheca, and a pair of oviducts open to the exterior through the female genital opening situated on the left and right sternites of sixth thoracic segment. The ovaries of P. sanguinolentus are categorized into five stages, according to the size, colour and external morphology of the ovaries. They are immature, early maturing, late maturing, ripe and spent. Fifty percent of the female crabs attained sexual maturity when they reached the size of 9.1- 9.5 cm CW. Fifty percent of the male crabs attained sexual maturity when they reached the size of 9.5-10.0 cm CW. However, the smallest berried female attained sexual maturity in the present study was measured at 8.6 cm CW. Based on the change in colour, increase in the size and change in the shape of the berry eggs, three different stages of egg development was observed. Stage-I has pale yellow to deep yellow coloured egg mass was 260.16 ± 0.24 μm. Stage-II has yellow to gray coloured egg mass was 290.2 ± 0.31 μm. Stage-III has deep gray to black coloured egg mass was 340.32 ± 0.34 μm.