Production Technology
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Game changer in freshwater prawn farming With genetic improvement of broodstock and mastering hatchery technology, GK Aqua is set to mass produce all male post larvae, bringing a new outlook on freshwater prawn farming in Malaysia By Zuridah Merican
Generation 4 Malaysian giant freshwater prawn broodstock at GK Aqua, Malaysia
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t has been six years since Giva Kuppusamy, CEO, founded GK Aqua (GKA), a Malaysia-based biotechnology startup to revive farming of the giant freshwater prawn Macrobrachium rosenbergii or udang galah in Bahasa Malaysia. With low supply, there is a lot of interest Malaysians are sentimental over this freshwater prawn. There is the Malay cuisine of cooking them in curries and the high-end Chinese Sang Har noodle dish. With aquaculture production declining to only 205 tonnes in 2019, 90% of demand (2,700 tonnes, DOF, 2019) was fulfilled with imports from India and Bangladesh. GKA has BioNexus status after securing investments of up to MYR3.5 million (USD0.8 million) from Malaysia government funds - Cradle, PlatCOM Ventures and SME Corp - for its initial phase; genetic improvement of the local stocks and to scale up hatchery technology for mass production. To reach an optimal number of larvae from broodstock, the bottleneck was a lack of understanding on maturation diets for the freshwater prawn. It is essential to have high survival rates along the supply chain - during the grow-out of post larvae as broodstock, spawning efficiency, nutrition and mastering hatchery technology. “Our initial years were difficult. There is the technology of rearing the post larvae to mature broodstock over 4 months. The rule of thumb was that each 40-50g broodstock will result in 20,000 larvae/spawn, assuming a 40% survival rate. With five spawnings per year, we can expect 50,000 post larvae/year calculated at 50% survival rate from larvae to post larvae (PL10-15),” said Giva as he recounted the early years of this startup. “Getting the hatchery technology right was a steep learning curve for the team. We needed volumes or farmers would be giving up on us. This happened in 2018 when our survival rate in the hatchery averaged only 1-2%. This business requires a lot of will power but GKA is ready to overcome both technical and business hurdles.”
From 2018 -2021, the focus was to improve broodstock grow-out and survival rates of larvae to post larvae with the help of experts from Thailand and Vietnam, respectively. Feeding broodstock with bloodworms and broodstock diets over 5-6 days yield 40-50% berried spawners. On their own, the team also learnt by trial and error, several critical requirements such as 200ppm alkalinity and 50ppm magnesium to push for more moults and speed post larvae growth. The breakthrough was in 2020 when it achieved mass production, stocking 150 larvae/L and consistently obtaining 50-60% survival rates. “Overall, our average survival rates gradually reached 30% which is an industry standard with wild broodstock. All the above depend on using quality albeit costly larval feeds and high crude protein vannamei and black tiger shrimp feeds,” added Giva. GKA has established itself as the only supplier of all male post larvae and juveniles in the country. “As a newbie in this industry, we need to continuously secure the trust of farmers, especially among the demanding first-generation industry players. We work hard to gain the trust of existing farmers and new entrants. Farmers trust us to supply all male post larvae/juveniles (guaranteed more than 90% all male) in each consignment. Also in 2018, we had a situation where mixed sex post larvae were distributed, which was disastrous for us.”
Reinventing the wheel for genetic improvement Genetic selection of local populations to produce all male populations was always in the plan for GKA. This was possible in 2018 when it received a grant of MYR864,000 (USD216,000) from PlatCOM Ventures. “We know that the demand is there. In the last 3 years, we have proven that farming of all male populations has several advantages.
May/June 2022 AQUA Culture Asia Pacific
