The main objectives are defined as follows :
* To develop mud crab broodstock maturation system, which promotes consistent spawning of good quality larvae: optimisation of hormonal implant, eyestalk ablation and feeding regime.
* To standardise hatchery production of Scylla serrata by improving zootechnics, feeding regime and microbial conditions : promotion of consistent and increased survival rates and quality postlarvae.
* To assess survival and growth rate of cultured vs. wild crabs after tagging and (re-) release, and evaluation of a sustainable technique for the cultivation of mud crab.
* To use recapture data to estimate population densities of wild mangrove crabs and measure impact of fishery effort.
* To include on above estimates of the effect of selective fishing on wild stocks e.g., fishing for juveniles for pond culture, immature for fattening and adults for marketing.
* To measure migrations and movements of (re-) released juveniles throughout the life cycle and compare with cultured juvenile release.
* To produce in hatchery different age or performance classes and assess survival and growth after release to identify most suitable groups for restocking purposes.
* To reduce costs for production of juveniles at economic scale under local backyard conditions.
1. A standard technique for mud crab broodstock maturation
2. A standard hatchery technique for production of mud crab postlarvae
3. A standard tagging technique for crab species
4. Mud crab population study in a defined area, including the impact of fisheries
5. Study on the impact of restocking on population characteristics of mud crab
The key activities involve :
* An experimental study on stock enhancement of the mud crab Scylla serrata and the possible impact of fisheries on it. Therefore, a specific biotope with a local mud crab population will be selected in Vietnam with the following advantages :
* confined area with control & monitoring possibilities over the mangrove crab population
* agreements with local fishermen on capture and recapture reporting
* local partner CTU is already involved in a mangrove replantation project for this biotope (IUCN fund of the Netherlands).
Restocking will be done with specific batches of tagged mud crab juveniles produced under controlled conditions in a local hatchery. The mark and recapture technique will be standardised and will allow to estimate fluxes of the population in natural mangrove.
* Testing of new technologies adopted from other larviculture operations (e.g. penaeid shrimp hatcheries) first at experimental scale in order to improve the consistency of production success of the hatchery operation and to guarantee the required fry quality. Optimised protocols will be integrated in a pilot-scale hatchery in Vietnam, allowing production of specific batches and the study of the profitability of mud crab hatchery operations.
Funding SchemeCSC - Cost-sharing contracts
LL59 5EY Gwynedd
92000 Can Tho, Province Hau Giang