Mangrove ecofarming in Guangxi Province China: an innovative approach to sustainable mangrove use

Following 7 years of field trials conducted in the mangrove areas of Guangxi Province, China, between 2007 and 2012, a mariculture system has been developed that greatly enhances natural productivity. This system is based on the installation of underground tubes and has resulted in annual mean production values of between 27 000, and 45 000 US$ per hectare¹ per annum without requiring cutting or conversion of mangrove vegetation. This article provides details of the system, its construction, operation, economics and production. Consisting of a network of underground tubes, erect pipes and management chambers, this system is based on enhancing the spatial heterogeneity of the benthic environment by burying plastic pipes in the mangrove soils, thus providing refuges for economically important fish with minimal disturbance to the mangrove root system. Landward shrimp ponds can be used as reservoirs to oxygenate the water in the system during low tide. Molluscs are raised on mudflat surfaces within the habitat. The ecofarming site is accessed by boardwalks that also facilitate ecotourism and public education. This ecofarming system is environmentally friendly because no enclosures are constructed and there is no industrial feed input. The bulk of the system is buried within the mangrove soils consequently it is resistant to storm and tidal surges, is easy to control and has low management cost, whilst the products are of high quality and have high recapture rates. To date, ten indigenous species have been tested, and five of them have been successfully raised and harvested. The underground tube ecofarming system is unique and not derived from any similar system currently in operation elsewhere in mangrove ecosystems.