Assessment of the Ovarian Maturation Stages of Mud Crab (Scylla olivacea)

Mud crab scientifically known as Scylla olivacea is a commercially important crab it provides a fundamental source of income for coastal fishing communities all through the Indo-Pacific region¹. Therefore, the production of mud crab through aquaculture is becoming vital as an export commodity in some countries.

Mud crab is considered as a significant export commodity. Southeast Asia had become one of the first regions to practice mud crab aqua farming by focusing on capture and fattening of the juvenile crabs from wild² because they are highly demanded all size classes.

Moreover, demand for orange mud crab has been amplifying due to its qualities such as large size, high meat yield³ as well as rapid growth during culture⁴.

Accordingly, scientists decided to conduct novel research for determining the female size at sexual maturity and to record the ovarian maturation stages of orange mud crab, S. olivacea through ovary external morphological as well as histological descriptions from the west coast of Peninsular Malaysia.

For this purpose, scientists recorded the carapace width and CW₅₀ for external morphological descriptions and the ovaries were utilized in the histological descriptions to study the size of their oocyte based on each ovarian maturation stages.

Conclusively, S. olivacea female CW₅₀ was found to be 8.9 cm. During this experiment, scientists observed that the ovary color alters in every ovarian maturation stage ranging from translucent for stage 1, yellowish during stage 2, orange in stage 3 and finally the ovary turned to dark orange during stage 4 when the ovary is well developed. Similarly, the size of the oocytes in the ovaries amplifies as the ovary developed further.

REFERENCES

1. Islam, M.S., K. Kodama and H. Kurokura, 2010. Ovarian development of the mud crab Scylla paramamosain in a tropical mangrove swamps, Thailand. J. Sci. Res., 2: 380-389.
2. Begum, M., M.M.R. Shah, A.A. Mamun and M.J. Alam, 2009. Comparative study of mud crab (Scylla serrata) fattening practices between two different systems in Bangladesh. J. Bangladesh Agric. Univ., 7: 151-156.
3. Rattanachote, A. and R. Dangwatanakul, 1992. Mud Crab, Scylla serrata (Forskal) Fattening in SuratThani Province. In: The Mud Crab, Angell, C.A. (Ed.). Queensland Department of Primary Industries, Queensland, Australia, pp: 171-177.
4. Millamena, O.M. and E.T. Quinito, 1999. Reproductive performance of pond-sourced Scylla serrata fed various broodstock diets. Proceedings of the International Scientific Forum of Mud Crab Aquaculture and Biology, April 21-24, 1997, Darwin, Australia, pp: 114-117.
5. Ikhwanuddin, M., J. Nur-Atika, A.B. Abol-Munafi and H. Muhd-Farouk, 2014. Reproductive biology on the gonad of female orange mud crab, Scylla olivacea (Herbst, 1796) from the West Coastal water of Peninsular Malaysia. Asian J. Cell Biol., 9: 14-22.