Soft-shell mud crab farming

Farming of soft-shell mud crab (Scylla serrata) has been practiced for some time now in a number of Asian countries. Because of its profitability, there is an increasing interest to engage in this aquaculture business venture. Crabs collected from the wild are the major source of stocks for farming. However, the use of hatchery reared crabs is encouraged so as not to deplete the wild population. Although communal rearing of crabs for soft-shell crab production in cages or in tanks is also practiced, this manual describes the individual rearing of crabs in boxes based on experience in Ranong, Thailand. The techniques can be modified depending on the site. This manual provides a section on the biology of mud crab that includes species identification, molting, and autotomy and regeneration which discloses important information related to the management of soft-shell crab farming. This is followed by a detailed discussion on the setting up and management of the farm for soft-shell crabs. The basis for the computation of cost and return analysis is included under the section on profitability. Cost of materials and labor varies in each country hence only the materials needed and other technical assumptions are listed as basis for computation

Biology and hatchery of mud crabs Scylla spp.

This manual describes the principles and procedures for spawning the mature crabs (Scylla serrata, S. tranquebarica, and S. olivacea) and rearing the zoeae to juveniles. Hatchery conditions should satisfy the ecological requirements of each specific stage, thus the manual starts with a section on biology of mud crabs.We thank the Crustacean Hatchery staff Emeterio Borlongan, Quirico Ganon, Eliseo Tisuela and Rudy Bravo for their competent technical assistance in the larval rearing runs, to Eduard Rodriguez for net cage nursery rearing, and to Jennette de Pedro for providing invaluable computer assistance. We are also grateful to Jurgenne Primavera, Milagros de la Peña, Nerissa Salayo, and Marietta Duray for sharing their expertise in improving this manual; Celia Lavilla-Torres for her contribution on diseases; AQD’s Publications Review Committee Relicardo Coloso, Teodora Bagarinao, Luis Maria Garcia, Gilda Po, and Wilfredo Yap for invaluable comments; Edgardo Ledesma for the line drawings; and to Rey Tenedero for the hatchery layout and other engineering aspects. Some of the results are based on the project 9217 funded by the Australian Centre for International Agricultural Research.1st Ed

Updates on the seed production of mud crab

Widespread interest in mud crab species is increasing because these are highly prized both in domestic and export markets. Among the three mud crab species commonly found in the Philippines, Scylla serrata, S. olivacea, and S. tranquebarica, S. serrata is preferred by farmers because it is larger and less aggressive than the other species. Likewise, S. serrata is the most widely distributed species in the Indo-west Pacific region. Hatchery-produced seedstock are presently used by some crab farmers in their grow-out operations. In the hatchery phase, feeding mud crab larvae with shrimp formulated diets and natural food was found to reduce the occurrence of molt death syndrome, one of the major problems in seed production. Larvae given 25% formulated diet (FD) + 75% natural food (NF; rotifers and Artemia) and 50% FD + 50% NF showed better performance than those larvae fed 100% FD, 100% NF and 75% FD + 25% NF indicating that usage of natural food, especially the expensive Artemia, can be reduced. Since the early crab instar (C) produced in the hatchery need to be grown further before stocking in grow-out ponds, two phases of nursery culture have been developed. C1-2 are grown to 1.5-2.0 cm carapace width (CW) size in the first phase and further grown to 3.0-4.0 cm CW in the second phase. Nursery rearing is done in net cages installed in ponds for easy retrieval. A combination of mussel or trash fish and formulated diet is used as feed. Domestication of the mud crab S. serrata as a prerequisite to selective breeding has been done at SEAFDEC/AQD. Likewise, defining criteria for the determination of quality of newly hatched zoeae for stocking in the hatchery was initiated. Newly hatched zoeae were subjected to starvation and stress test using formalin. Starvation failed to elicit responses that were significantly different between the good and poor quality larvae hence it is not suitable for larval quality evaluation. Based on three-year data, the formalin stress test gave mean cumulative mortalities of 2.38±0.32, 8.24±0.88, 20±1.58 in good quality larvae, and 43.74±2.39 while 22.93±4.19, 63.68±7.17, 84.29±3.88 and 97.65±1.06 for poor quality larvae at 0 (control), 20, 30 and 40 ppm formalin, respectively. As formalin level increased, cumulative larval mortality also increased regardless of the quality of the larvae. Formalin stress test proved to be a reliable method to determine whether a batch of newly hatched zoeae was of good or poor quality

Proceedings of the Regional Technical Consultation on Stock Enhancement for Threatened Species of International Concern, Iloilo City, Philippines, 13-15 July 2005

This 150-page book documents the proceedings of an experts' consultation held at AQD in July 2005. It contains nine review papers and seven country papers

Prawn hatchery operations

The manual, an updated version of the 1984 SEAFDEC/AQD manual, presents the underlying principles and step-by-step instructions of prawn larval and post-larval rearing. The techniques described are not only applicable to Penaeus monodon, but may also be modified and applied to other penaeid and metapenaeid species. The following aspects are covered: Site selection; Life cycle; Hatchery design and planning; Hatchery operations; Diseases; and Economics.Rev. Ed

Reproductive performance of captive Penaeus monodon fed various sources of carotenoids

Three groups of pond-reared Penaeus monodon broodstock were fed formulated diet in combination with carotenoid-containing natural food: mussel + shrimp broodstock pellet (MBP), crab + BP (CBP), and Artemia + BP (ABP). After four months, maturation and spawning rates did not differ significantly among treatments. After eyestalk ablation, MBP-fed shrimps Initially spawned 20 days; 34 days for CBP-fed; 50 days for ABP-fed shrimps. The number of eggs per g body weight of spawner (1616-2359 eggs /g BW) did not differ significantly among all groups. Only nauplii from MBP-fed broodstock reached postlarval stage. Rematuration was observed only in MBP- and CBP fed shrimps. Sperm count was highest in MBP- and lowest in ABP-fed shrimps at the final phase of the test