A new form of fish farming, known as cage culture, is expanding in flowing water of rivers and canals in various parts of the country, raising hopes for an increased production of fish.
Fishes, mostly tilapia, are now farmed in nearly 6,000 cages in rivers where such farming did not exist even a decade ago.
The practice, under which fishes are grown in mesh enclosures, has expanded as farmers have found it to be profitable because of the scope to grow a higher quantity of fishes in cages compared to ponds, according to fisheries officials, farmers and researchers.
Consequently, the fisheries and livestock ministry is working to frame a policy on cage culture in inland water, which remains untapped despite the huge potential to augment production of fish.
“We have taken an initiative to frame a policy to ensure organised expansion of the cage-based farming,” said Syed Arif Azad, director-general of the Department of Fisheries (DoF).
He said cages are being built in rivers in a scattered manner and roles and responsibilities of stakeholders are not clear.
“The land ministry is the owner of the rivers while we grow fish. The private sector is also involved,” he said.
Bangladesh has 8.53 lakh hectare areas of rivers and estuaries, and public water bodies represent lakes and swamps, according to the DoF.
Fisheries officials said cage culture can't only increase the overall production but also raise the contribution of open water bodies to the annual production of fishes.
Some 27 percent of the 38.78 lakh tonnes of fishes were produced in open water bodies in 2015-16. Aquaculture accounted for 56 percent of the total fish output in the year, according to the DoF.
Officials said cage culture is practised in many countries in Asia, Europe, and North America. Bangladesh saw the beginning of the farming in the 1990s, according to Azad.
“New technologies of fish farming are coming up. We can't keep our water pool like rivers idle,” he said.
The draft policy said cage culture is not flourishing as expected in absence of legally supported user rights to grow fish in flowing water, also depriving the government of revenues.
The draft policy seeks to include all flowing rivers and water bodies that are suitable for cage culture. It said interested people will have to apply to an upazila committee stating the name and location of the water body where they want to do cage culture.
A committee headed by the deputy commissioner will select the successful applicants based on the recommendations of the upazila committee, according to the draft.
The draft policy said cages should be built in an area having 10-feet depth and cages should be three foot above the bottom of the river.
Some 10-15 percent of the water bodies in the country can be used for cage culture if floating feed is used. On the other hand, cages could be established on 5 percent area of a river if sinking fish feed is used, according to the policy.
Mosharef Hossain Chowdhury, president of the Bangladesh Cage Culture Association, said cage culture in a flowing river is more profitable than farming in ponds.
“This is because of the leverage to grow more fish in cages than in ponds,” he said.
A 200-square-feet cage can yield 700 fishes compared 150 fishes in the same area in ponds, according to Chowdhury.
Chowdhury began growing tilapia fish in 15 cages in the Dakatia river in Chandpur in 2008. Encouraged by high margins, he went on to increase the number of cages to 150 cages at one point.
He, however, reduced the number of cages to 40 in the face of soaring prices of feed, rising movement of vessels and oil spill from the vessels plying on the river.
He said the rising prices of feed have put farmers in a tight spot as prices of fishes, particularly tilapia, have not gone up because of the increase of production and supply of other fishes.
Chowdhury said a policy on cage culture would yield a good result, as there is still a huge opportunity in Bangladesh.
Md Asadul Baqui, district fisheries officer in Chandpur, also said the number of cages had risen faster when the farming method was introduced. Later, the growth slowed owing to the rising prices of feed. “Many poor farmers had to quit because of the high prices of feed,” he said.
Chandpur is one of the pioneering districts in cage culture in the country.
Prof Md Anwarul Islam, a former vice-chancellor of Bangladesh Agricultural University, said the cage culture could be a practical solution to boost fish production as land is scarce to make ponds for aquaculture.
Citing his experience, he said, during winter, fishes grow well in rivers because of higher temperature compared to that of in ponds.
The farming of fish in cages is not without environmental concern.
Islam said water quality of rivers can deteriorate if cages are put in place miles after miles. This can happen in the rivers that have low depth and slow flow of water. “Biodiversity of rivers and its water quality would not be affected if cages are established in a planned manner,” he said.
Another concern is rivers are a major source of other types of fishes, but all fishes are not suitable for cage culture. “Farmers will incur losses unless cage cultures are expanded without finding proper technology and workforce,” said Islam.
Md Abdul Matin, general secretary of the Bangladesh Poribesh Andolon, said the water flow in rivers would be slow because of the obstruction imposed by setting up of a large number of cages.
River water is likely to be polluted if a chemical feed is used. Also, there is a possibility of constructing structures centring cages, he said.
In order to address the environmental concerns, the DoF plans to allow cage culture in certain areas of a river, not in the whole river.
“We will assess the impact if we get a proposal for a large project,” said Azad, of the DoF, adding that the draft policy would be posted on the DoF's website for feedbacks.