Aquaculture is a rapidly expanding sector globally, with India being the second-largest producer of aquaculture resources and contributing approximately 6.3% to global aquaculture production. The state of West Bengal, with its long, serrated coastline, has a vast potential for aquaculture. It is the largest producer of tiger prawns in the country, most of which are cultured in the rapidly expanding aquaculture areas of the Sundarbans Biosphere Reserve (SBR).
Is the expansion of aquaculture, in response to growing market demand and profitability, a threat to this critically vulnerable coastal area? Or is it a means for sustainable development of the local communities struggling to adapt to accelerating climate change impacts?
The SBR is a unique mangrove forest comprising a network of mudflats and low-lying islands at the confluence of the populous Ganges river delta in West Bengal, India, with the royal Bengal tiger as its flagship species. It is a UNESCO World Heritage Site, spanning 9,630 sq. kms. across core and buffer forest areas and a transition zone. As many as 4.43 million people inhabit the transition zone (5,367 sq. kms. area) and traditionally practice rainfed agriculture, artisanal fishing and forest collection for their subsistence.
Large-scale clearance of mangrove areas in the 19th century transformed the Sundarbans into a settlement for revenue generation by the colonial regime. Freshwater flow to the region diminished with time so that river water, and even the groundwater in many places, is brackish-to-saline.
While some farmers traditionally practiced freshwater aquaculture in backyard ponds, brackish water aquaculture (BWA) proliferated low-lying areas adjacent to river banks and creeks when globalisation brought the international demand for prawns to the doorstep of the mangrove forest.
A range of socioeconomic and environmental drivers, supported by a significant lack of vision for sustainable development, has led to the rapid growth of BWA at the expense of over 1,000 hectares of mangrove forest, 2,322 hectares of eco-sensitive mudflats and 2,4000 hectares of multi-crop agricultural land, defying coastal regulations.
While some part of the land conversion can be attributed to the terrible legacy of cyclone Aila (2009), which rendered agricultural lands in some cyclone-affected areas unfit for cultivation for several years, salinisation is not the foremost driver of rapid aquaculture expansion in the SBR.
The promise of higher profitability from commercial aquaculture enticed farmers to illegally convert their agricultural fields to aquafarms.
In the last few decades, erratic monsoon alongside temperature rise on land and sea, frequent cyclones and floods, a high rate of coastal erosion, and the rising cost of fertilisers and farming, have gradually reduced agricultural productivity and driven more and more farmers to adapt by shifting to aquaculture….