Evaluation of the potential for restocking natural mangroves with juvenile Scylla serrata cultured under controlled conditions in an experimental hatchery. 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. Optimized 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.