Present and future scenarios of changing land use patterns from the perspective of agroecosystem under the shadow of ever-expanding shrimp culture

Abstract

Conversion of cultivation lands into shallow water bodies is a trend in several shrimp growing regions in the world. The main aim of this research is to evaluate the current and future eco-economic scenarios of these converted lands for shrimp culture through the perspective of agroecosystem. To analyze the cost-benefits of respective lands, financial data with and without addition of some hidden costs associated with shrimp production for three specific sites were compared of Purba Medinipur district, West Bengal, India. One of these three sites was a control site located outside the range of shrimp culture with agricultural activities; one was affected site, adjacent to shrimp farms with agricultural activities and the third was the leased land for shrimp culture. Vital abiotic components of soil were studied and compared between these three sites in order to distinguish specific changes caused by the shrimp culture. As well as the large scale temporal changes due to land conversion was visualised by satellite images. From the interpretation of the cost-benefit analysis, switching from leasing to re-cultivation has the lowest profitability in terms of Net Present Value. Net present value for the leased land became negative at 5% discount rate and above, during re-cultivation after the end of leasing tenure. Adjacent affected farms are equally vulnerable to the gradual production loss and would have no viable alternative to leasing for fishery. Significant differences in soil components were found between these sites. The entire ecological nature of the lands is altered when fertile lands are converted into shrimp farms. Finally, the ecological functional imbalance impacts the economic outcomes from the lands. It causes non-sustainable changes throughout the agricultural landscape. This study result is flagship to interlink between the growing of shrimp economy with the local agro-economy and agro-ecosystem for all shrimp growing regions in the world, especially south Asian shrimp producing countries. Some top-down policy measures were discussed in order to achieve a sustainable balance between the agroecosystem and shrimp culture.