Strategies to tackle salinity intrusion
Shrimp culture is referred as the best adaptation to salinity intrusion by many researchers. The government of Bangladesh and international donors heavily patronized this industry which resulted in 61% contribution of total fish export earnings in 2014-15.
But the salinity level at present in Khulna, Satkhira, and Bagerhat is rising beyond the tolerance of shrimp.
Shrimp culture was started in Bangladesh between late 70s to early 80s. The industry grew rapidly in the mid-90s and became extremely profitable.
But the problem started when farmers started to cultivate brackish water tiger shrimp (Bagda) which was highly subsidized by the government and NGOs.
Over the years, the salinity level increased beyond tolerance by the natural process of diffusion.
Tidal surges and cyclones are often made responsible for the intrusion of saline water into the coastal inlands. But the truth is that shrimp farming-induced activities are more responsible for salinization than cyclones and tidal surges.
Polders that were constructed to resist saline water intrusion were made porous to supply saline water to the Bagdaghers. Eventually, the polders failed to withstand even Cyclone Aila, a category-1 cyclone.
Rice farmlands were converted to Bagdaghers overnight, as many landlords invested heavily. As a result, many farmers lost theirs lands and became jobless as shrimp culture requires fewer labourers.
A hectare of ghers requires one or two labourers to look after. Thousands of farmers were forced to migrate or displace somewhere else to find their livelihoods.
Shrimp production started to decline after 2014. In 1996,salinity level in Satkhira was 15 ppt which increased to 46 ppt in 2016 by the natural process of diffusion from ghers. Bagda can survive salinity from 2-40 ppt.
Now the gher owners shifted from shrimp to crab, as crab can tolerate up to 60 ppt and obviously for its huge demand in the international market. Many investors are now investing in crab, including cricketer Shakib Al Hasan.
Governments and NGOs are subsidizing crab farming also, like they did for shrimp.
In October 2018, I went to Shyamnagar, Satkhira to attend a seminar arranged by Independent University, Bangladesh (IUB) headed by Bhobotosh Kumar, chairman of Burigoalini Union, where he talked about the socio-economic impact of salinity and about how efficiently the government supported crab farming adaptation.
He did not have an answer when I asked him about the government’s plan after 10 years, when the salinity would exceed 60 ppt beyond the tolerance of crab.
Talking to many locals of Shyamnagar, I came to know that many in their neighbourhoods are facing kidney complexities, and women are suffering from hypertension during pregnancy. These health problems are clear indications that the salinity has already reached the ground-water table.
Now, after all these issues, should we refer to shrimp and crab farming as perfect adaptation strategies to salinity intrusion, climate change, and sea level rise?
According to Intergovernmental Panel on Climate Change (IPCC), adaptation is defined as adjustments in human and natural systems, in response to actual or expected climate stimuli or their effects, that moderate harm or exploit beneficial opportunities.
If we see through the lens of the Pressure and Release Model of Vulnerability, shrimp and crab farming is actually making the locals more vulnerable to an upcoming disaster.
Shrimp and crab farming might seem to be the best adaptation strategies to salinity intrusion for the time being, but in the long run, these are not successful adaptations. It’s high time we focused on mitigation rather than adaptation.
SM Abdullah Al Mamun is a freelance contributor.