International Seminar-Workshop on Mud Crab Aquaculture and Fisheries Management (ISMAF 2013)

Proceedings of the International Seminar-Workshop on Mud Crab Aquaculture and Fisheries Management, 10-12 April 2013, Tamil Nadu, India

Thu, 01 Jan 2015 00:00:00 GMT

Proceedings of the International Seminar-Workshop on Mud Crab Aquaculture and Fisheries Management, 10-12 April 2013, Tamil Nadu, India Quinitio, Emilia T.; Estepa, Fe Dolores P.; Thampi Sam Raj, Yohannan C.; Mandal, Anup

Development of practical diet for the grow-out culture of Scylla serrata in ponds

Thu, 01 Jan 2015 00:00:00 GMT

Development of practical diet for the grow-out culture of Scylla serrata in ponds Catacutan, Mae R.; Mallare, Mae F.; Quinitio, Emilia T. Quinitio, Emilia T.; Estepa, Fe Dolores P.; Thampi Sam Raj, Yohannan C.; Mandal, Anup A series of feeding experiments were conducted in the laboratory and in ponds of SEAFDEC/AQD using hatchery-produced Scylla serrata juveniles to develop an effective pelleted grow-out diet. The practical feed ingredients included local and imported fishmeal, shrimp meal, copra meal, soybean meal, corn grits and squid liver powder. The other feed ingredients were rice bran, wheat pollard, bread flour and micronutrient mixes. The results in the laboratory trials were used to improve the feed composition for the culture of crab juveniles in grow-out ponds. Three runs (Run 1 - 108 days, Run 2 - 129 days and Run 3 - 114 days) were conducted in 270m2 ponds. Crab juveniles at stocking densities of 0.08 - 0.10m-2 were fed two dietary treatments containing 44% and 38% crude protein at similar dietary energy level estimated at 17 MJ/kg diet. There were no significant differences in the survival, growth and feed conversion ratio in each of the three runs. In Run 1, the survival rate of crabs fed with 44% protein was higher (56-77%) than crabs fed with 38% protein (35-50%), but these were not significantly different. In Run 2, < 5 g crabs could grow up to a mean body weight of 435 g with survival rates of 31- 45% after 129 days on a ration consisting of 80% pelleted formulated feed and 20% low value fish. Similarly in Run 3, a mean of 443 g was attained in less than 4 months with survival rates of 30-73%. The final average weight and specific growth rate of crabs fed these two diets were not significantly different which showed that in ponds, the 38% crude protein diet was able to sustain growth as with the 44% diet provided the dietary energy is similar. The feed conversion ratio for both test diets and low value fish showed a great variation (low value fish 1 to 4; test diets 1.81 to 5.6). This study showed that low value fish as the traditional feed for mud crab in the grow-out culture can be decreased to only 20% of the ration by incorporating 80% of formulated pelleted feed.

Soft-shell crab production using hatchery-produced mangrove crab Scylla serrata juveniles

Thu, 01 Jan 2015 00:00:00 GMT

Soft-shell crab production using hatchery-produced mangrove crab Scylla serrata juveniles Ganesh, K.; Dinakaran, G. K.; Sundaresan, T.; Satheesh Kumar, K.; Gangadharan, K. V.; Viswanathan, S.; Pandiarajan, S.; Thampi Sam Raj, Yohannan C. Quinitio, Emilia T.; Estepa, Fe Dolores P.; Thampi Sam Raj, Yohannan C.; Mandal, Anup Soft-shell crab production is being practiced in many Asian countries but the major source of seedstock is from the wild, which could no longer sustain the increasing demand. Commercial scale soft-shell crab production can become sustainable only if there is a continuous supply of seedstock not dependent on wild stock. Rajiv Gandhi Centre for Aquaculture (RGCA) under the Marine Products Export Development Authority (MPEDA) has established a pilot-scale mud crab hatchery at Thoduvai, Nagapattinam District, Tamilnadu in 2004 with the technical assistance from SEAFDEC/AQD. At present, RGCA has the biggest mud crab hatchery in India and a demonstration farm at Karaikal, U.T. of Puducherry, where nursery rearing, grow-out and soft-shell crab production are conducted using hatchery- produced mangrove crabs or mud crabs, Scylla serrata. This paper presents the results of the soft-shell crab production using hatcheryproduced S. serrata juveniles maintained in perforated low density polyethylene (LDPE) boxes. The duration of the molt interval, time of molt (day or night) and the increase in body weight and carapace width of each size group (40-60, 61-80, 81-100, 101-120, 121-140, 141-160, 161-180 g) after molting were determined. Results showed that the percentage increase in body weight and carapace width increased as the crabs grew bigger. Likewise, the molt interval was longer in bigger-sized groups of crabs. Sixty to seventy percent of the population molted during night time and the next molt occurred within 25 days in 80-160 g size groups. Soft-shell crabs in boxes within the water surface and juvenile crabs (2.5 cm CW initial size) for culture until market size in the pond can be a viable technology technology for mud crab growers.

Culture of Scylla serrata (Forskal) in cement ponds

Thu, 01 Jan 2015 00:00:00 GMT

Culture of Scylla serrata (Forskal) in cement ponds Kotiya, A. S.; Solanki, J. B.; Akolkar, N. G. Quinitio, Emilia T.; Estepa, Fe Dolores P.; Thampi Sam Raj, Yohannan C.; Mandal, Anup Male and female Scylla serrata juvenile crabs were stocked separately in cement ponds (14 x 8 x 0.8 m; 90 m3) and reared for 90 days. The study was conducted at the Fisheries Research Station, JAU. Okha, Gujarat. The crabs were fed trash fish and Trochus spp. The survival rates of male and female crabs were higher in Run 1 at 66.11% and 45.55%, respectively, than in Run 2 at 13.9% and 6.1%, respectively. The mean body weights of males (1,704 g) and females (994.5g) in Run 1 were higher compared to those in Run 2 (381.2 g for males and 104.5 g for females). However, there were no significant differences (P>0.05) in the average daily weight gain of 0.19 g day^-1 for males and 0.13 g day-1 for females in Run 1 and 0.16 g day-1 for males and 0.13 g day^-1 for females in Run 2. The water parameter levels were within the optimum ranges for mud crab culture. The results indicate that it is not commercially viable to grow juveniles to market size in cement ponds based on the conditions in this study.