Crab farming has surged in recent years across the salinity-prone coastal district of Satkhira, with many farmers shifting from shrimp farming to crabs due to the species’ resilience to climate conditions and high commercial value. However, the increased farming activity has led to a growing environmental problem, as discarded crab shells were often left to rot, causing pollution and odor issues. Aslam Hossain saw a solution where others saw waste and launched a venture that turns these shells into a commercially viable organic fertilizer.

Aslam’s innovation addresses two key issues: it reduces waste from crab farming while providing a sustainable alternative to chemical fertilizers. His business has been financially supported by the Palli Karma-Sahayak Foundation (PKSF) and the World Bank under their Sustainable Enterprise Project (SEP), with additional local backing from the Nawabenki Ganamukhi Foundation (NGF).

The production process for Magiccompost is relatively straightforward. Crab shells are collected from local farms, dried, and ground into powder using a machine. These are then mixed with decomposing vegetables, collected from local markets and households, and left to decompose for up to two months. The final product is a nutrient-rich organic fertilizer, which is sun-dried, packaged, and sold at a profit. Magiccompost costs between $0.11-$0.13 to produce per kilogram, and is sold for $0.25 per kilogram.

Since its inception in 2021, the fertilizer has gained a growing customer base, with local shrimp farmers and vegetable growers using it to improve yields. Aslam’s enterprise has already caught the attention of 30 local shrimp farms and 20 commercial vegetable growers, who are utilizing the fertilizer to boost their production. The demand for Magiccompost is also rising among urban gardeners, many of whom place their orders through social media platforms like Facebook.

Crab farming in Satkhira has been on the rise due to the species’ climate resilience and lower susceptibility to diseases compared to shrimp. However, the increased production of crabs has also led to a rise in waste, with most crab shells previously discarded in rivers and landfills, leading to environmental degradation. By transforming this waste into a valuable fertilizer, Aslam is not only contributing to sustainable farming but also earning a monthly income of $250-$420.

Aslam Hossain’s long-term goal is to expand Magiccompost’s reach across the country, under his own brand name. He is currently in the process of obtaining approval from the Bangladesh Standards and Testing Institution (BSTI), which will allow him to market the fertilizer more widely. He also plans to scale up production, but requires additional infrastructure and investment to meet growing demand.

“Crab shell fertilizer has the potential to revolutionize sustainable farming in Bangladesh,” Aslam said. “With the right investment, we can expand production and provide farmers with an environmentally friendly alternative to chemical fertilizers, while also tackling the waste problem in the crab farming industry.”

Aslam’s family has a long history in shrimp farming, with seven acres of land currently under shrimp cultivation. However, his success with Magiccompost has prompted him to focus more on sustainable solutions for agriculture.

The initiative stands as a prime example of how innovative thinking can turn environmental challenges into profitable and sustainable ventures. It is a story that not only benefits the local economy but also contributes to the global movement towards sustainable farming and waste management.

In a region grappling with the dual pressures of climate change and environmental degradation, Aslam Hossain’s Magiccompost is proving that solutions can be found by looking at challenges from a new perspective. With support from local organizations and potential investors, the future looks promising for this sustainable initiative.

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Fertilizers encourage the growth of planktonic algae, which are a source of food for many fish, by increasing the availability of key nutrients. Animals that consume algae are also produced as a result of fertilization, including some fish like the Chinese silver carp and the Nile tilapia.

Farmers employ pond fertilization to increase a water body’s biological productivity, which enhances fish growth and abundance.

Nutrients enhance the growth of microscopic plants (phytoplankton) in the water when ponds are fertilized . Fish consume zooplankton and larger creatures, both of which are fed on by phytoplankton. The growth of rooted aquatic weeds can be hampered and light from reaching the pond bottom can be blocked by an overabundance of these microscopic plants, which can also generate a “bloom” in the water. Fish farmers and owners of recreational farm ponds fertilize their water bodies to increase fish output and prevent the formation of rooted aquatic weeds. Enhancing the amount of naturally occurring food (phytoplankton and zooplankton) available to fry, larval fish, or species that are efficient filter feeders is the goal of fertilizing aquaculture ponds.

Which pond should not be fertilized?

Before you start, there are a few things to bear in mind. Firstly, you should determine the alkalinity of your ponds. Agricultural limestone should be put to ponds with low alkalinity before beginning a fertilization program. Before beginning a fertilization program, have it tested if you are unsure of the alkalinity. Moreover, there should be no tolerance for algae or vegetation when fertilizing. An essential first step in creating the optimal fish habitat is to inspect the pond before fertilizing it. Prior to fertilizing, any undesirable vegetation or algae should be treated.

Ponds with dominant undesirable fish species should also wait to be fertilized until those fish have been removed. Even while uneaten food is an extra source of nutrients, it is usually not essential to fertilize catfish ponds when the fish are frequently fed. Fish growth is greatly aided by feeding catfish in ponds with low alkalinity water.

Until the issue is resolved, ponds that are murky, have weed infestations, or experience excessive water flow shouldn’t be fertilized. Mud blocks water’s access to light, which slows the growth of phytoplankton. It is never a good idea to fertilize weedy ponds because the nutrients will only encourage the growth of additional weeds rather than phytoplankton.

Fertilizer nutrients are diluted and rendered useless by excessive water flow, which occurs when the volume of the pond is altered in less than two weeks. Moreover, nutrients that are pushed out of the pond can contaminate streams.

Choosing appropriate fertilizer:

Any retailer of agriculture supplies will have fertilizers available. Unless the product contains additional components that may be detrimental to fish or other aquatic species, any fertilizer formulation with the right nutrition levels can be used, even if some are made expressly for ponds.

For improved outcomes, pick phosphorus-mixing fertilizer. There are three main kinds of inorganic fertilizer available which are liquid, powdered and granular. The easiest forms of fertilizer to dissolve are liquid, powdered and then granular. Although powder is more expensive than liquid or granular versions, it is quite simple to use.

A great fisheries management strategy that will boost the number of fish a pond can host is fertilization. Ponds that have been properly fertilized can support three to four times as many fish as ponds that have not been treated. Although clear water may be pleasing for the eye, it lacks the phytoplankton and zooplankton that form the basis of the aquatic food chain. A healthy plankton bloom throughout the growing season gives small fish a plentiful food source and aids in their ability to fend off predators.

Farhana Islam
Agriculturist, Researcher
Fisheries Resource Management, CVASU

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