INJECTION OF HORMONE EXTRACTED FROM HERBS AS EFFECTIVE MOULTING STIMULATOR ON MUD CRAB (Scylla sp.)

Herlinah Jompa*and Early Septiningsih
Research Institute for Coastal Aquaculture
Jl. Makmur Dg. Sitakka No.129 Maros, South Sulawesi,
Indonesia90511,
hjompa@yahoo.com

Soft-shell crab production is one of strategy to increase production of cultured crab. Although soft-shell crab is economically beneficial, most of the farmers cannot continue their business because of long farming period and molting event is not simultaneous. This study was aimed to analyze the effectiveness of mulberry (Morus spp.) as the source of ecdysteroid as physiological manipulation to stimulate the moulting and to result simultaneous moulting on mud crabs.

This study was conducted in a 2,500 m2 of pond in Crab Research Installation of Maranak Village, belongs to The Research Institute for Coastal Aquaculture. Sample of crabs, 7-10 cm width and 45-100 gram weight were reared for 60 days. The Completely Randomized Design was applied with three treatments and 5 replications.

The variables measured in this study were percentage of moulting crab, mortality, absolute and daily growth rates. Samples of crabs were injected using 1 mL of the extracts whereas crabs in control were not injected with any extract, yet, feed with trash fish. The crabs were then put in the rearing box with stocking density 1 ind./box. Daily visual observation was conducted during the study. The crabs were harvested just after they moulting by replacing them from their boxes then stored them at separated boxes. The moulting crabs were then allowed for 1 hour before the measurements of final weight, width and the body length.

The results of the study indicated that extract of mulberry resulted higher moulting percentage and daily growth rate compared to that observed on crabs injected with other plant and trash fish (Table 1). These findings indicated that extract mulberry is effective in triggering moulting on crab and also support the growth of reared crabs.