Genetically selected carp strains amplify Bangladesh's smallholder aquaculture profits amid systemic pond degradation and climate pressures

Indigenous polyculture systems in Bengal historically relied on diverse carp species like *mola* (*Amblypharyngodon mola*), which provide micronutrients and ecological balance, but these are being replaced by monoculture strains optimized for profit. The loss of traditional knowledge about pond ecology—such as the role of aquatic plants in oxygenating water—undermines the long-term sustainability of these systems. Corporate seed systems displace farmer-managed seed banks, eroding genetic diversity and cultural practices tied to specific fish varieties.

The Green Revolution’s introduction of high-yield varieties in agriculture serves as a cautionary parallel, where short-term productivity gains led to soil degradation, biodiversity loss, and farmer indebtedness. Bangladesh’s aquaculture sector has followed a similar trajectory, with state policies favoring export-oriented shrimp farming in the 1980s–90s, which devastated mangrove ecosystems and displaced coastal communities. The current focus on genetically selected carp echoes colonial-era botanical interventions, where external expertise was imposed over local adaptive practices.

In Java, Indonesia, smallholder farmers use *mina padi* systems to integrate carp with rice cultivation, achieving higher yields and resilience to droughts without external inputs. Indigenous communities in the Amazon cultivate *piaractus brachypomus* (pacu) in floodplain ponds, maintaining genetic diversity through seasonal migrations—a practice absent in Bangladesh’s static pond systems. These systems demonstrate that polyculture’s success depends on ecological mimicry, not just genetic selection.

The study’s focus on growth rate and profit margins overlooks the ecological trade-offs of monoculture, such as increased vulnerability to disease and the need for synthetic feed inputs. Research on polyculture systems in India shows that integrating multiple carp species can reduce feed costs by 30% while improving water quality, yet this evidence is sidelined in favor of corporate-led genetic solutions. The scientific literature on aquatic biodiversity highlights that genetic selection often reduces resilience to climate stressors like salinity spikes.

In Bengali folk art, carp are symbols of fertility and prosperity, depicted in *patachitra* paintings as harbingers of good harvests—a cultural value erased by the commodification of fish as profit-driven commodities. The spiritual significance of ponds as sacred spaces in Hinduism and Buddhism is undermined by their transformation into industrial production units. Artistic traditions that celebrate biodiversity, such as *alpona* (floor art) depicting diverse fish, are fading as monoculture systems dominate.

Climate projections for Bangladesh indicate that salinity intrusion will render 30% of coastal ponds unsuitable for freshwater aquaculture by 2050, threatening the viability of genetically selected carp strains. Scenario modeling suggests that polyculture systems integrating salt-tolerant species like *Labeo rohita* hybrids could maintain productivity under future conditions. However, current research prioritizes short-term profit over long-term adaptation strategies, risking systemic collapse.

Landless women farmers, who often manage smaller ponds with limited access to improved strains, are excluded from the benefits of genetic selection, exacerbating gender inequalities in aquaculture. Indigenous communities like the Chakma and Marma in the Chittagong Hill Tracts have traditional knowledge of pond ecosystems but face displacement due to state-backed aquaculture expansion. The focus on corporate-controlled seed systems further marginalizes farmer-led innovation and seed sovereignty movements.