Shellfish Breeding and Hatchery Management (2+1)

9.2.3 Mud crab broodstock collection and transportation

9.2.3 Mud crab brood stock - collection, transportation, acclimatization and management

Live mature male and female S. tranquebarica and S. serrata can be obtained from the inshore sea and brackish water regions where these mud crabs form a commercial fishery.

Transport of broodstock

Generally live mud crabs are tied with jute / nylon thread to arrest the movement of chelipeds for easy handling. Live adult crabs obtained from the fishermen / merchants are dipped in fresh and clean sea / brackishwater in order to moisten the gills and packed in bamboo baskets with wet sea grass / seaweeds and are transported either by road or rail or air. By this method of packing, mud crabs are known to survive for a maximum period of 3 - 4 days.

If the duration of transport is longer, those crabs with all limbs intact are given another dip in sea / brackishwater and packed in new bamboo baskets en route. This will ensure their survival for another 3-4 days.

In another method, adult crabs weighing 350-700g are packed at the rate of one crab per packet in polythene bags each containing six litres of oxygenated seawater after placing plastic sticking tape over the chelipeds and a tight plastic tube over the tip (dactylus) of walking legs and transported by road, rail or air for a duration of 24 hours.

Prophylactic treatment of broodstock

Mud crabs obtained either from the wild or from the culture ponds should be disinfected individually in 100ppm Formalin for 30 minutes before transferring them to the broodstock holding thanks.

Acclimatization of broodstock

After disinfection, the adult mud crabs should be held in tanks containing sea water (30 to 35 ppt), for a week, in order to acclimatize them to the hatchery conditions, before the initiation of trials on induced maturation and breeding.