WorldFish says its G3 Rohu grows 30pc faster

The generation 3 or G3 Rohu developed by WorldFish grows more than 30 percent quicker than the available strains in Bangladesh, according to the international nonprofit research institution.

WorldFish expects thousands of Bangladeshi farmers to purchase G3 Rohu seed this year. This strain of the fish will become more widely available in the market, WorldFish said in an event co-hosted by the Bangladesh Agricultural Journalist Forum.

Bangladesh produces 4.5 million tonnes of fish per year, according to the Department of Fisheries. Inland aquaculture accounts for 57 percent of the fish, at 2.6 million tonnes. However, due to a lack of genetically improved fish seeds, Bangladeshi farmers are not receiving the expected benefits and profits from Rohu farming, WorldFish said.

"We can obtain more fish in the future if we nurture the genetically improved strain like G3," said WorldFish Senior Scientist Benoy Kumar Barman, adding that they want to double the production by 2040.

"People may think that G3 will be harmful, but nothing is harmful here. This strain was chosen after a thorough selection process. We collected spawn from several rivers and selected the best. This G3 is just the best of the best."

In 2020 and 2021, WorldFish introduced this genetically improved G3 Rohu strain to many hatcheries on a trial basis. The hatcheries grew these fish and began generating genetically improved seeds for nurseries and farmers to purchase.

“WorldFish-developed G3 Rohu will play a significant role in realising the government’s view of increased fish production in the coming years," said Firoz Ahmed, district fisheries officer of Jashore.

With the gathering of spawn from the Halda, Padma, and Jamuna rivers, the WorldFish Rohu Genetic Improvement Program began in 2012.

WorldFish established an on-farm performance trial involving 19 semi-commercial farms in Rajshahi and Khulna divisions. According to WorldFish, these semi-commercial farms represent the largest proportion of Bangladesh's fish farms.

The trial’s objective was to assess the growth performance of G3 Rohu compared to an unimproved Rohu strain, descended from fish collected from the Halda, Padma, and Jamuna rivers, and a well-regarded commercial strain, collected from a hatchery. All three Rohu strains were spawned at the same time and the resulting hatchlings were nursed at the WorldFish Carp Genetic Improvement facility near Jashore.

In May 2021, tagged fish were distributed to the trial farms and reared by the 19 farmers together with other fish species according to their usual farming practices. At harvest, between March and June 2022, G3 Rohu was ranked first in all 19 farms and on average, G3 fish weighed 37 percent more than the fish from the unimproved strain.

Mohammed Yeasin, the dissemination manager based at WorldFish, said, “We hope that the experience of early-adopting farmers and the results of this trial will motivate many more farmers to adopt this genetically improved Rohu strain in the coming years.’’ 

He also hoped the next generations of Rohu will post even higher growth rates.

WorldFish is working on improving the genetics of the Catla and silver carp breeds. With the release of more mature generations of Rohu and other species in the future, the agricultural output of carp polyculture systems in Bangladesh is expected to increase, Yeasin said.