76 DECEMBER • WORLD AQUACULTURE • WWW.WAS.ORG Giant freshwater prawns The giant freshwater prawn is one of the most significant cultivable species in freshwater systems because of its high price, big size, fast growth rate, good flavour and strong export and domestic demand at high value. There are about 200 species in the genus Macrobrachium, and over 30 of them are found in India. Three commercially important species, namely M. gangeticum, M. malcolmsonii, and M. rosenbergii, are found in India. In their early life stages, M. rosenbergii need brackish water (approximately 12 ppt salinity). They are bottomdwelling, nocturnal and mostly detritus feeders in nature but with cannibalistic behaviour, especially during moulting. In culture systems they can be fed on pelletized feed with high protein content. Bangladesh, Brazil, China, Ecuador, India, Malaysia, and Thailand have historically been top producers of M. rosenbergii. Sexual dimorphism is present in this prawn, with males somewhat larger than females. M. rosenbergii attains maturity in four months and reproduces from July to December in India, with peak breeding activity taking place with the arrival of the rainy season (Figure 2). Only mature females that have recently finished their pre-mating moult, shedding their soft shells, can successfully mate with males, who have hard shells. The adult male releases and deposits a gelatinous mass of spermatophore between the female’s walking legs on the underside of the thoracic area during mating. After copulation, eggs are extruded from gonopores, fertilized and then attached to pleopods in the brood chamber on the ventral side of the abdomen. During a single spawning, a fully-grown female prawn can deposit 0.08-0.1 million eggs or 500 eggs/gm body weight. Aquaculture is an important food production system, providing livelihood and nutritional security to a large population in India. Due to its high nutritional value and lowpriced animal protein, fish plays an important role in reducing malnutrition among millions of undernourished people across the globe. India produced 17.54 million tons fish in 2022-23, becoming third third-largest fish-producing country in the world. India accounts for 8% of global fish production, which contributes about 1.09% to the country’s Gross Value Added (GVA) and 6.72% to the agricultural GVA. More than 80% of Bihar’s population live in rural areas, where agriculture and allied sectors are the cornerstone for their employment. Farmers of Bihar have realized a vast opportunity of aquaculture in the state, therefore, they are converting their agriculture land for fish farming. Now, farmers are inclined to adopt new technologies to improve production and productivity from the water bodies. Adoption of recent advanced technologies has boosted aquaculture in Bihar, resulting in production of 0.85 million tons fish in the state during 2022-23. About 90% of the fish production in Bihar depends on three species, specifically Catla (Catla Catla), Rohu (Labeo rohita) and Mrigal (Cirrhinus mrigala). Recently, some farmers have shown interest in species diversification in the form of Pangas catfish (Pangasianodon hyphophthalmus) farming, but high input costs limit the interest of many fish farmers. With a dearth of suitable freshwater fish species to keep the pace in momentum of fish farming, giant freshwater prawn (Macrobrachium rosenbergii) can be a potential candidate species in Bihar (Figure 1). Giant freshwater prawn can be adopted for all kinds of aquaculture practices like monoculture, polyculture and integrated fish farming. Giant Freshwater Prawn (Macrobrachium rosenbergii): A Potential Candidate Species in Aquaculture Diversification in Bihar, India Tarkeshwar Kumar, Vivekanand Bharti, Kamal Sarma, S.K. Ahirwal and Anup Das FIGURE 1. Giant freshwater prawn. Aquaculture is an important food production system, providing livelihood and nutritional security to a large population in India. Due to its high nutritional value and low-priced animal protein, fish plays an important role in reducing malnutrition among millions of undernourished people across the globe.
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