Vermi with aquaculture : A tool for increasing farmer's income

Shah Mustahid Hussain / P Debnath / RK Saha / Mahesh Pathak *

Profitability in aquaculture is influenced by utilization of renewable resources leading to concept of organic and natural farming.

Vermicomposting is one of the most important among various components of organic and natural farming. It is also dynamic aspect of earthworm bio-technology at present. When organic matter is subjected to decomposition with the help of earthworms, the resultant product is vermicompost and the process is known as vermi-composting.

Earthworms are considered as excellent bioreactors for waste recycling; vermicom-posting is thus an effective mode of waste management, nutrient recycling and sustainable organic farming. Vermicomposting technology can be particularly useful for the management of waste from agriculture, city garbage, livestock, sewage and industrial organic wastes etc.

Vermicompost is already in use in agriculture. In fish farming, feed management is one of the costliest and most important components which help to produce potential yield of fish giving high returns to the farmer.

Vermi is a good protein source and that can be properly utilized as a major feed source in aquaculture. So, in aquaculture, waste can be more profitably utilized and commercialized through vermi- composting.

Vermi cum aquaculture farming

Integrated aquaculture-agriculture-vermiculture farm can be entirely synergistic. The water body where farming of aquatic organism is being practiced can be supported by animal waste, silk work pupae, earthworms and byproduct of human food grain in the form of fish feed or manure to increase natural productivity.

The water of pond can be used for irrigating agricultural and horticultural crops as well as rearing live stock. A vermiculture-sericulture-carnivorous fish culture is an important approach. Experiences have shown in some small ditches, where Clarias batrachus (English Name: Walking cat fish) and Heteropneustes fossilis (Common Name: Singhi) were fed with earthworms and silkworm pupae, prevention of cannibalism even in high stocking density.

In a vermicompost farm in Akshay Krishi Vikash, Mahisbathan, Nadia successfully yielded organically produced agriculture and aquaculture products using vermicompost as manure. Researchers from different part of the world reported that the biomass generated as a byproduct of vermicomposting has been found to be a good source of protein for fish.

Attempts are now being made in the fish farming industry to replace the costly fish meal which is normally incorporated in diets with alternate and cheaper sources of protein. In Japan, the demand for processed earthworms as feed for eel fry is 180,000 tonnes annually. Vermicompost is also used as organic manure in agricultural fields, though its efficacy in the aquaculture system has not yet been properly evaluated.

Considering all these points, studies on utilization of the product i.e., vermicompost and earthworm in aquaculture is of great importance.

Effect of vermicompost-bred earthworms, vermiwash on fish growth

Earthworms are unique as fish food as they contain many essential amino acids along with hemoglobin in their blood serum, which provide the required iron for developing fish. Adult earthworm, cocoons and vermiwash can serve the purpose of fish feed in different ways. Fish is mostly consumed as a delicacy with little knowledge of its nutritional wealth.

Nutrition is core pillar of human development. High prevalence of low birth weight, high morbidity and mortality in children and poor maternal nutrition of the mother continue to be major nutritional concerns in India. Clearly, this situation emphasizes the need for examining several issues of nutritional significance. One among the issues is the dearth of information about the nutritional benefits of our food.

A study claimed that protein and carbohydrate content was higher in earthworm fed fish compared to that in fish with control diet. The lipid content was lower in earthworm fed fish compared to that in fish with control diet. The study concludes that earthworm fed fish has better nutritional impact than fish with control diet. This study suggested that earthworm feed is superior feed for fish instead of artificial feed.

It is reported that the growth and survival rate of fishes were significantly higher in the vermiwash fed fishes, possibly due to the presence of several micronutrients, metabolites, vitamins (Pro vitamin D and B complex) and also for some free amino acids in vermiwash. The juvenile fish are able to take very small food particles present in vermiwash.

The common food particles like live plankton feed or market available feed pallet, are much larger (3 times larger than particles present in Verm wash under ocular microscope) than food particles the juvenile fish can consume.

Vermicompost as pond fertilizer

Fertilization and organic manuring is widely practiced in aquaculture ponds for increasing pond productivity as well as to reduce expenditure on feeds and fertilizers. Various types of animal manures such as, cow dung, poultry manure and duck manure are successfully used for this purpose.

The goal of fertilization is to enhance primary, secondary and tertiary levels of productivity towards maximum yield of fish. Application of vermi-compost as organic manure in fish farming ponds is a new concept and research is still going on for further explorations.

Vermi-compost can be utilized as food for invertebrate fish food organisms as well as for fishes for direct consumption; they are intended primarily to release inorganic nutrients in water body for phyto & zooplankton growth, earthworm casts contain 2-5 times more organic matter, total nitrogen and exchangeable cations than soil which improves sediment quality.

So, vermicompost not only supplies nutrients but also improved the physio-chemical properties of water as well as the qualities of sediment base.

Economics of vermicomposting

The total cost of vermicompost production was derived by adding variable cost and fixed cost. Most of the vermicompost producers use the variable inputs available at home for vermicompost production. The small-scale production in the household can obtain around Rs 3000 profit per month with B:C ratio of about 1.47. However, in large scale or commercial production, we can get more profit.

Conclusion

Vermicomposting is now a better option for the farmers for sustainable agriculture and higher income. It is not only easy to prepare but its environmental benefits are huge. Since advantage of vermicompost over chemical fertilizers is high, farmers are shifting towards it. There are more advantages of vermiculture than disadvantages of vermicomposting. Hence, scientists are suggesting farmers to use them.

In organic aquaculture systems, vermicomposting provides the use of a holistic farming system, which is an autonomous organic agro-ecosystem, based on partnership with nature. The main advantage of vermicompost is the recycling, reduction and reuse of the agricultural waste which is helps sustain the environment.

Further more, huge quantities of domestic agricultural and rural industrial wastes can be recycled through the process, which is an urgent need of the day. Healthy fish with higher yield can be harvested in aquaculture with the incorporation of Vermin as a food component which is rich in nutrition and organic in nature.

Moreover, vermicompost can also be used as manure for production of phytoplankton which enhances the zooplankton production thereby.


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