52 MARCH 2026 • WORLD AQUACULTURE • WWW.WAS.ORG Freshwater prawns are widely consumed across the globe, much like marine shrimps. Among various genera, Macrobrachium and particularly M. rosenbergii (commonly known as giant fresh water prawn) is of significant commercial importance due to its high demand and suitability for aquaculture. Freshwater prawn farming is predominantly practiced in tropical and subtropical regions, especially in southeast Asian countries like China, India, Bangladesh, Indonesia, Malaysia, Thailand, and Vietnam. M. rosenbergii is the most cultured freshwater prawn species globally. In addition, species like M. nipponesis, M. orientalis and M. malcomsoni are also farmed depending on the availability of seed from hatcheries and natural waterbody resources. Among the top ten cultured species worldwide M. nipponesis and M. orientalis stand out with current annual production of 2.6 and 2 thousand tons, respectively. Many potential Macrobrachium candidate species that have no complete breeding technology are produced from capture or capture-based culture fisheries. Macrobrachium lar (the Monkey River prawn, Figure 1), native to the Indo-west Pacific region, has demonstrated its potential importance in culture due to its fast growth rate and large size (Ghazi and Hasan 2021). Historically, the major constraint to the culture of this species was procurement for grow-out due to difficulty in larval rearing practices. The freshwater prawn industry in India is primarily dominated by M. rosenbergi, and according to production data from the Marine Products Export Development Authority (MPEDA 2023) the total production in 202122 was 21,317 tons, nearly 50% lower than the 42,800 tons produced in 2005. To revitalize and expand this sector the culture of alternative freshwater prawn species is essential. Among these M. lar, native to freshwater habitats in Andaman and Nicobar, has emerged as a potential candidate for commercial production. Morphological Characteristics of Macrobrachium lar Macrobrachoium lar shares many similarities with M. rosenbergii. It has a sigmoid shaped rostrum with 7-9 dorsal teeth compared to the 8-13 found in M. rosenbergii (New et al. 2009). Mature male M. lar are easily distinguished by their large, long, and robust pereopods with cutting edge incisors. Specifically, in the second pereopod the merus is longer than the carpus, which is the reverse in M. rosenbergii. Females are smaller than males with shorter thoracic legs and more slender heads, and they often carry fertilized eggs on their pleopods. The sexual dimorphism of M. lar is similar to that of M. rosenbergii. In M. lar populations, three male morphotypes can be distinguished by claw colour and their relative size ranges within the population. The adult males have three distinct forms. Black claw (BC) males are relatively large with long stout chelate legs; orange or brownish claw (OC) males have mediumsized claws, and small males (SM) possess short delicate claws compared to other two forms. Biology of Macrobrachium lar The first report of Macrobrachium lar was from India (Cai and Ng 2002). This species can be found from East Africa to the Marquesas Islands in the Indo-west Pacific region. The species is also native to the Andaman and Nicobar Islands of India as reported by many sources. After completing larval development in sea water it moves to fresh water at the juvenile stage (Figure 2). This species shows an upstream feeding migration in freshwater streams from lower elevations, and it is found in freshwater streams, pools, and water falls that are connected to the sea. M. lar inhabits welloxygenated pools beneath riffles and waterfalls and is also found in wetlands and swamps with taro and other aquatic plants. Individuals typically shelter in piles of rocks, brush, burrows, fallen trees and among tree roots. Brooders are usually found in upper section of streams, where Macrobrachium lar (Monkey River prawn): A Potential Candidate Species for Aquaculture in Andaman Islands Chittaranjan Raul, R. Kiruba Sankar, J. Praveenraj and Udipta Roy FIGURE 1. Macrobrachium lar. © H.T. Cheng
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