AbstractCoastal shrimp farming has been contributing significantly to the socio-economic development of many tropical countries. This industry, however, is now of great environmental concern regarding mangrove deforestation and eutrophication of coastal waterways. Rapid development of coastal shrimp farming in Quang Ninh Province, Vietnam, adjacent to the World Heritage-listed Ha Long Bay, over the last decade may lead to unrecognized and undesirable environmental impacts. Hence, this study aimed to investigate key coastal management issues in Quang Ninh including the contraction and expansion of mangroves and shrimp farms, and the impacts of shrimp farm effluent on water/sediment quality of receiving waterways.
Satellite images were used to detect land cover/land use change at two study sites (Ha Long and Mong Cai) between 1999 and 2008. The results showed that mangrove areas reduced by an estimated 2,071.9 ha while shrimp farming areas increased by 2,898.4 ha over the same period. Although shrimp farming was the main reason for mangrove loss in Mong Cai, shrimp farms in Ha Long were mainly constructed on areas previously comprising bare soil or waterways.
Water and sediment samples from tidal creeks receiving shrimp farm effluent were collected and analyzed for spatial and temporal variation. Spatial variation was found with high levels of nutrient and nutrient-related parameters (dissolved inorganic nitrogen, total phosphorus, biochemical oxygen demand, chlorophyll-a in water; total nitrogen, total phosphorus, total organic carbon in sediment) at channels/creeks adjacent to shrimp farms with these levels declining in the same creeks 2–3 km away from the effluent discharged points. Water quality was found to vary temporally with nutrient levels elevated after shrimp crops, especially for sampling sites adjacent to shrimp farms.
From the findings, strategies for improving the existing management regime to promote sustainable management of coastal shrimp farming and broader environmental protection of the study area are discussed.
|Date of Award||2012|
|Supervisor||Stefan Maier (Supervisor), Chris Austin (Supervisor) & Jim Luong-Van (Supervisor)|