Aquaculture & Fisheries

Biography

Biography: Roel H Bosma

Abstract

The expansion of shrimp aquaculture went often at the expense of mangrove forest. Following declines in productivity as a result of deteriorating quality of bottom and water and subsequent outbreaks of shrimp diseases, farmers either reverted to very extensive or to more intensive production systems. Some countries successfully controlled mangrove clearance after 1990 along the coastline but in example Indonesia the ponds extended up to the shores. In the process Philippine’s farmers developed the green-water system (GWS) which reduces disease impact and improves shrimp growth. After massive mangrove clearance trade-offs on fisheries and coastal protection became apparent. According to recent studies the Total Economic Value of intact mangrove is higher than the profits earned from intensive shrimp culture. Other studies show that mangrove’s nursery function can be well maintained, if the remaining areas of mangrove are well connected to the aquatic ecosystem and not fragmented. However, expanding the ponds up to the shores demonstrates to be detrimental for land accretion while sea level rises and land subsides due to example fresh water extraction. In many cases, the benefits of extensive systems are too small to repair dikes and pond infrastructures after abrasion. Through a modelling approach we demonstrate that the total benefits for society of a sound mix of aquaculture and mangrove are higher than from either full intact mangrove or a completely transformed landscape. Mixed mangrove shrimp systems can contribute to the societal