Asadul Islam peers into his pond in south-west Bangladesh and watches as hundreds of caged crabs float past beneath him. He is looking for those that have shed their hard shell. When he finds one, he has a short window to freeze it and send it off for sale to westerners with a taste for soft-shelled crabs. He hopes this new business venture will provide the wealth that eluded his father. For generations, Islam’s family farmed rice. But from the 1980s, rising seas and storm surges began pushing saltwater over the banks of tidal rivers and ruining their crops. His father, along with millions of other coastal farmers, decided to flood the family’s paddies with brackish water and stock the briny ponds with black tiger prawn fry. Backed by the Bangladeshi government, which saw tiger prawns, or shrimp as they are generally known, as a lucrative export opportunity, and development organisations that heralded the transition from paddy to pond as a clever climate-change adaptation, more than 275,000 hectares (680,000 acres) have been flooded, mostly in the south-west, for intensive aquaculture. If farmers could not keep seawater from poisoning their fields, they could use it to grow something else. It was a way to adapt, and for a while it worked. Commercial prawns, known as “white gold”, became one of Bangladesh’s most valuable exports. However, the trade-off for a few years of income has been decades of environmental degradation and sometimes violent conflict, showing how some adaptations can make people more, not less, vulnerable. “Shrimp aquaculture has been called a climate-change adaptation strategy. Some development agencies say it’s the only option for areas already going under water,” says Kasia Paprocki, a geographer at the London School of Economics, and author of Threatening Dystopias: The Global Politics of Climate Change Adaptation in Bangladesh. “But it contributes to many of the social and ecological problems it claims to avert.” Bangladesh faces rising seas, intensifying cyclones, extensive flooding and extreme heat, and while the country struggles to protect itself from the effects of the climate crisis, its south-west region is reeling from the unintended consequences of a shrimp farming boom – a solution that became a problem. Islam lives on Gabura, an island surrounded by the Kholpatua River perched north of the Bay of Bengal and the dense Sundarbans mangrove forest. It’s a precarious place to call home for the 40,000 people who live there. After Cyclone Amphan made landfall here in May 2020, parts of the island sat underwater for most of the next 18 months. Today, people are shoring up their mud houses, sealing their dinghies with fresh black tar and readying for another cyclone season. Bangladesh’s government has committed about $108m (£88m) to fixing the island’s crumbling protective embankments. But even if the work is completed – and many locals doubt it will be – Gabura remains poisoned from within. In the last three decades, more than two-thirds of its farmable land has become a silver desert of saline shrimp ponds. These heavily fertilised lagoons quickly became breeding grounds for diseases such as white-spot baculovirus, which attacks prawns’ bodies and can destroy a crop within a week. To compensate for losses, farmers often overstock ponds, but the strategy is unsustainable. “The virus first attacked about 10 years ago,” Islam says. “We started with 500 shrimp but then had to increase to 1,000, and then 3,000 in the same place because so many shrimp died.” Side-effects from intensive shrimp farming have incubated conflict in impoverished rural communities. Crop farmers complain that brackish water leaking from shrimp ponds poisons their fields. Environmentalists say that feed and fertilisers damage local biodiversity. Unemployed people complain that raising shrimp requires a fraction of the labour required to grow rice, and the hungry watch as the land’s fertility is used to raise a product prioritised for export. Even drinking water has suffered – salt taints more than 50% of aquifers in coastal Bangladesh – and although cyclones and relentless tides deserve much of the blame, so does the proliferation of brackish aquaculture. Only one well on Gabura is deep enough to bring up fresh water, so locals depend on six surface pools that collect rainwater for drinking, cleaning and bathing. According to a government study from 2019, three of those pools were used for aquaculture, and just one provided safe drinking water. The freshwater crisis has taken an outsize toll on women, intensifying existing gender inequalities. In areas with high salinity, women and adolescent girls travel commonly travel 3.5 miles a day in search of drinking water for their families. Anyone hoping to address these issues must contend with the money that aquaculture brings to a country that is developing aggressively. In the year before the Covid pandemic severed global supply lines, Bangladesh exported 30,000 tonnes of shrimp worth nearly $350m (£290m). Since the 1980s, development agencies have pushed shrimp farming as a means of lifting coastal communities out of poverty, says Paprocki, despite the tensions it has created, and findings that it has had little impact on poverty. Experts say the lion’s share of the revenue has been captured by industry middlemen and wealthy landowners with political ties. This “shrimp mafia”, as those who control the industry are often referred to locally, have used intimidation and, at times, violence to control the trade. One of the worst incidents, says Topon Gualdar, a rice and vegetable farmer in a village 40 miles north of Gabura, happened in 1990 when a wealthy businessman brought an armed gang to forcibly cut an embankment so the land could be flooded and seized for shrimp ponds. “We protested hard,” Gualdar says. “We did not want to destroy our trees, land, water, our livelihoods.” During the standoff, the gang killed a woman. But Gualdar and the others resisted, and the village’s fields are still lush with paddies and vegetable gardens. Similar uprisings have occurred elsewhere, but on Gabura, where holes and pipes that suck brackish water through the embankments weakened the island’s fortifications before Cyclone Amphan, locals say action to defend the land is unlikely. A water devlopment board engineer said that when the embankment is rebuilt, shrimp farming in Gabura will be limited to a designated area to avoid conflict. However, investigations by Transparency International Bangladesh, an anti-corruption organisation, found that water board officials and local politicians often resolve embankment-cutting cases in favour of shrimp farmers. “As a result, such illegal cutting is still ongoing,” a 2020 report from the organisation found. Bangladesh is racing to stay ahead of rising waters and needs money to protect its people – between $3bn and $8bn by 2030 for adaptation measures, according to some estimates. In this environment, industries that generate significant economic activity take on a shine, even if their problems are well documented. There are alternatives – including less-intensive methods of raising shrimp and co-operative ownership models that protect community values – but the priority given to intensive prawn aquaculture leaves little room for a local vision of how the region might otherwise adapt to climate change, Paprocki says. On Gabura, Islam hopes his investment in soft-shell crabs will pay off better than his father’s gamble on shrimp, but there’s no way to be sure. He learned the business from a Japanese frozen seafood company that was seeking producers. It seemed like a smart move: crabs fetch a higher price than shrimp, and he was told they were less vulnerable to disease. Barring any more global shutdowns, trade disruptions or environmental disasters, he says he is optimistic about the future, although business is off to a rough start. This winter’s cold temperatures killed 1,200 of his 2,000 crabs. He will stay up late, tending to the survivors, and will sell what he can in the morning.