Mangroves have always naturally protected tropical coastlines from erosion. More recently, shrimp farms have applied pressures to the natural forests. In response to the clearing of the forests, mangrove ‘greenbelts’ are being used to prevent coastal erosion.
Joan Martinez-Alier, from the Department of Economics and Economic History, Universitat Autònoma de Barcelona, Spain has published a report entitled Ecological Conflicts and Valuation – mangroves vs. shrimp in the late 1990s. From the abstract:
Shrimps are produced in two different ways. They are fished in the sea (sometimes at the cost of turtle destruction) or they are “farmed” in ponds in coastal areas. Such aquaculture is increasing around the world as shrimps become a valuable item of world trade. Mangrove forests are sacrificed for commercial shrimp farming. This paper considers the conflict between mangrove conservation and shrimp exports in different countries. Who has title to the mangroves, who wins and who loses in this tragedy of enclosures? Which languages of valuation are used by different actors in order to compare the increase in shrimp exports and the losses in livelihoods and in environmental services? The economic valuation of damages is only one of the possible languages of valuation which are relevant in practice. Who has the power to impose a particular language of valuation?
From the Introduction:
In many coastal areas of the tropical world, in Ecuador, Honduras, Sri Lanka, Thailand, Indonesia, India, Bangladesh, Philippines, Malaysia, there is social resistance against the introduction of shrimp farming for export, since this implies the uprooting of mangroves in order to build the ponds. In such areas, poor people live sustainably in or near the mangrove forests, by collecting shellfish, by fishing, by making use of mangrove wood for charcoal and building materials. The mangroves are usually public land in all countries, being in the tidal zone, but governments give private concessions for shrimp farming or the land is enclosed illegally by shrimp growers. Illegality is prevalent not only because of the public character of the land, but also because there are often specific environmental laws and court decisions protecting the mangroves as valuable ecosystems.
Shrimp or prawn production entails the uprooting of the mangroves, and the loss of livelihood of people living directly from, and also selling, mangrove products. Beyond direct human livelihood, other functions of mangroves are also lost, perhaps irreversibly, such as coastal defence against sea level rise, breeding grounds for fish, carbon sinks, repositories of biodiversity (e.g. genetic resources resistant to salinity), together with aesthetic values. Pollution from the shrimp ponds destroys the local fisheries. Also, wild shrimp disappear because of the loss of breeding grounds in mangroves and because they are overharvested as seed for the ponds.