The close proximity of mangroves to the ocean makes them ideal locations for shrimp farming and other kinds of mariculture. Further, they are areas rich in nutrients, and part of larger wetland systems, making them attractive as agricultural areas. Finally, these areas near the sea are prized for salt production. As a result, hundreds of thousands of hectares of mangrove forests have been cleared, and the hydrology has been altered, in order to intensify commercial production of shrimp and other species, cultivate agricultural crops, and create salt ponds. The delicate tidal regimes are interrupted and the balance between fresh and salt water is lost. The intensive mariculture operations are most often constructed for export. The shrimp and other species that are raised and harvested from the artificial ponds are fed specific diets that often include chemicals. Extra nutrients from the concentration of food and animals cause eutrophication, which harms the surrounding marine habitats by lowering oxygen levels and changing species distributions. The chemicals enter the food chain and can harm nearby species. Shrimp farm activity alone has been responsible for the loss of 38 percent of the world’s healthy mangroves; the percent climbs to 52 if all agricultural activities are counted (Ellison 2008). Between 1980 and 2005, shrimp and salt production together were responsible for the loss of 85,000 and 80,000 hectares of mangroves in Honduras and Panama, respectively (FAO 2007). If world demand continues for farmed shrimp and other mariculture species, then they must be farmed in land-based facilities, with state-of-the-art water treatment facilities and environmentally responsible management plans. Non-mangrove areas where trees have already been cleared can be used for agriculture and salt ponds.
Ellison, A. M. 2008. Managing mangroves with benthic biodiversity in mind: Moving beyond roving banditry. J Sea Res 59: 2–15.
Food and Agriculture Organization of the United Nations (FAO). 2007. The world's mangroves 1980-2005. Chapter 6. North and Central America. FAO Forestry Paper 153.