This post is written by the "Advancing Aquaculture Systems Productivity Through Carp Genetic Improvement" project team of the Feed the Future Innovation Lab for Fish and originally appeared on the Fish Innovation Lab website. The project team would like to thank partner hatcheries, participating farmers, and Department of Fisheries in Bangladesh for their ongoing engagement, participation, and interest in these trials.

Most farmers of livestock and crops have long had access to genetically improved breeds and varieties, but that has not been the case for carp farmers such as Shafiujjaman Momin from Bagatipara upazila of Natore District in northwest Bangladesh. At least, not until now.

Momin is taking part in a trial of third-generation (G3) WorldFish genetically improved rohu. WorldFish G3 rohu (Labeo rohita or rui) is expected to grow 30 percent more rapidly than river-sourced fish. The purpose of the trial, in which Momin is taking part, is to validate these predicted growth rates under real-world, on-farm conditions.

“When I received the G3 rohu from WorldFish, I was told that this fish would grow 30 percent faster than the conventional strain. I did not believe it then,” said Momin. “However, I see it is growing even faster than 30 percent, so now, I have confidence in G3 and believe it can help fish farmers produce more with less.”

Last year, hatchlings from rapidly growing WorldFish G3 families were made available to hatcheries to be grown into breeding parents (i.e., brood stock). It is the performance of these same G3 families that Momin is trialing on his farm, along with rohu from a well-regarded commercial strain and rohu from an unimproved control line (equivalent to river-sourced rohu).

Under a Feed the Future Innovation Lab for Fish project — led by WorldFish, Bangladesh Agricultural University, and the Louisiana State University Agricultural Center — Momin and 18 other semi-commercial farmers were provided with trial fish in May 2021. He is now growing them with multiple other species (i.e., under polyculture), according to his usual farming practices. This trial is being undertaken with additional support from the CGIAR Research Program on Fish Agrifood Systems (FISH), the Bill & Melinda Gates Foundation, and Feed the Future Bangladesh Aquaculture Activity. Preliminary measurements taken in September revealed that the growth of G3 fish, relative to the control line fish, was in line with expectations. Final results will be available before the G3 brood stock supplied to hatcheries become reproductively mature and their offspring are made available for sale to nurseries and farmers.

Waiting for rohu

Rohu hatcheries, nurseries, farmers and researchers are waiting expectantly for these results. It is anticipated that around 20 hatcheries will sell approximately 3,500 kilograms of hatchlings to more than 35,000 nurseries and farmers in 2022 and 2023.

“I collected G3 rohu from WorldFish in 2020,” says Ekramul Kabir, the proprietor of Madhumoty Fish Hatchery in Jashore, Bangladesh. “Since then, I have been rearing the fish at my hatchery facility to prepare them for spawning in 2022. Currently, each fish weighs one kilogram on average, which is much better than any conventional rohu strain.

“I learned that a field trial is underway to evaluate the performance of G3 rohu at the farmer level. If the trial result is similarly encouraging, it will be useful for us to help farmers understand the advantages of this improved rohu strain.”

In addition to rohu, WorldFish manages catla (Catla catla) and silver carp (Hypophthalmichthys molitrix) genetic improvement programs. Although not as advanced as rohu, G1 catla families were produced in 2021, and G2 silver carp will be spawned in 2022 with support from the Fish Innovation Lab project.

An exciting step for Bangladeshi aquaculture

Fish accounts for 60 percent of animal protein consumed in Bangladesh. This is predominantly sourced from domestic aquaculture, and rohu is a culturally and economically important species in the country. It has a wholesale market value of around $1 billion each year. In this context, on-farm trials and adoption of WorldFish G3 rohu is an exciting step forward for Bangladeshi aquaculture, but it is just the beginning.

Thanks to the support from the Fish Innovation Lab, WorldFish produced additional G3 families in 2021, and in 2022, it will produce its first fourth-generation (G4) families. WorldFish G4 is expected to grow at least 40 percent more rapidly than river-sourced rohu.

Such rapid genetic gains are unheard of in terrestrial animal and crop breeding. When it comes to genetic improvement, the sky is the limit for aquaculture species with their short generation intervals (two to three years for carp) and no history of domestication.

Once in the hands of hatcheries, nurseries and farmers, genetically improved rohu, catla, and silver carp will further enhance the productivity of carp polyculture systems in Bangladesh. Accordingly, it will contribute to increased food security, nutrition, and livelihoods for the farmers and consumers that rely on these carp polyculture systems.