Is aquaculture abandonment a threat to sustainable coastal resource use? – A case study of Andhra Pradesh, India, with options for reuse

Abstract

The conversion of important ecosystems and land used for other purposes to aquaculture and abandonment after short-term use threatens coastal resources. The spatial extent and location of abandoned aquaculture farms were explored in this study based on land use change detection and trajectories in the Krishna District of Andhra Pradesh, India, as a case study using the Geographic Information System (GIS), satellite data, spatial analysis techniques, and field verification. Satellite image interpretation keys for abandoned aquaculture were identified. The brackishwater aquaculture area increased by 387% from 1990 to 2000, then decreased by 19% in 2006, and further decreased by 47% in 2009. As a result, 6648 ha of shrimp farms were abandoned in 2006. This number further increased to 13,493 ha in 2009. The introduction of the Penaeus vannamei culture in 2009 has increased the shrimp farm growth by 35% in 2015 and revived 11% of the unused aquaculture farms. Considering the rise and fall of the extent of shrimp farms, overall 30.6% of the shrimp farms were abandoned in 2015. Markov chain analysis indicates that the abandoned aquaculture area will be 11,512 ha in 2021 and that the conversion of agricultural land into shrimp farms continues. The soil characteristics of abandoned shrimp ponds and the water quality of source waterbodies near unused areas indicate the potential of the reuse for shrimp farming based on suitable management practices. Identification of the prior land use of abandoned shrimp farms such as mangroves, agricultural land, has given the options for reuse. Efforts need to be made to revive abandoned shrimp farms; otherwise, they may lead to unsustainable resource use in major shrimp-growing countries worldwide.