Fish farming, usually done in large ponds, has now moved indoors and is taking up less space as Bangladeshi aquaculture tries its luck at using biofloc technology (BFT).
Biofloc technology was developed in the 1990s as a way for fish and shrimp farmers to conserve feed inputs and utilize wastewater during production by piggybacking off the nitrogen cycle and letting beneficial bacterial colonies proliferate in culture water.
According to some experts, this method uses only 3.3% of the water and land required by ponds, making it very sustainable.
For instance, the use of BFT has enabled Aarsh Agro Limited — a company located in Jalalabad Housing Society, Chittagong — to produce nearly 30 times more fish compared to conventional pond farming.
The company started its operations in April last year and is run by four people: Md Wais Hossain, the chairman; Shafeen Sana Chowdhury, managing director; Mizanur Rahman, executive director, and Md Awsaf Hossain.
Aarsh Agro is also in the process of expanding through another project in Mawna, Sreepur upazila, which will help boost production facilities from 200,000 litres to 2 million litres.
In recent years, there have been a lot of fisheries that have adopted this method but not everyone has been able to make it sustainable due to various reasons such as not being able to procure accessories for the system and a lack of experienced people in the sector.
After observing that there is a growing demand for low-cost protein sources, the founders of the company decided to cater to that market.
“In a country like Bangladesh where millions were facing hardships especially during the pandemic, we looked for ways to solve that issue. Given that we had limited knowledge in the field when we started, we spent a month on feasibility studies, researching case studies, research papers and YouTube tutorials, after which in mid-April last year, we arrived at the biofloc solution with a pilot project of a 10,000-litre-capacity,” said Shafeen Sana Chowdhury.
However, they did face obstacles, such as not finding reliable sources for good quality fry.
Transportation of the fry was a big challenge, according to the team, especially for their Chittagong project as it had to be transported long distances from Mymensingh and Bogura.
“High feed costs are another issue, as due to the pandemic, fish prices are also low in the market. We are educating and training ourselves and are currently working with consultants to mitigate the issues we have,” Chowdhury added.
When it comes to food, there are certain chemicals and nutrients that have to be added in the tanks from time to time from which the fish sustain.
Even though these nutrients are often available, there are various low-quality alternatives that these farmers have to be careful of.
Aarsh Agro currently employs five people who are in charge of maintaining the process. Apart from that, the owners also contribute their time to the fishery.
“Using only an acre of land, we can now achieve the same output as a 30-acre pond. It is a simple technology, which is purely organic,” said Wais.
He added: “The difference lies in the science of combining probiotic and fish waste into floc which becomes food and balance for the aquaculture — oxygen, nitrogen, and ammonia. The final result is the high-density growth for fish within a calculated time frame.”
According to the owners, if there were grants from the government or even soft loans available, then many more would also join in and develop the sector further.
They had to make an investment of Tk50 lakh to start the project.
“We fixed a target that by 2030, we will expand in sustainable ways to meet Bangladesh’s protein deficit. For this, we plan to scale up our capacity with quality fish while updating the technology from time to time,” Wais added.
But producing fish using this method is not a cakewalk.
According to a research paper published in Biotica Research Today, the technology requires active management to be successful.
The system requires a start-up period and yields are not always consistent between seasons. Since producers must constantly mix and aerate culture water, energy costs could be higher than expected.
In addition to these factors, producers must actively manage the biofloc ponds to prevent nitrite accumulation and to keep alkalinity levels remaining within a healthy range.
Monitoring fish health and welfare is also key as bioflocs can increase the levels of suspended solids in the water, leaving fish and shrimp susceptible to environmental stress.
