Cryopreservation — preserving and storing the sperm cells of fish — helps maintain valuable genetic material and supports the growing aquaculture sector in the country
Fish farmers in Bangladesh harvesting Fish Innovation Lab carp. Photo credit: M. Gulam Hussain/Feed the Future Innovation Lab for Fish
In Bangladesh, a team of researchers is harnessing the power of cryopreservation to help fish farmers produce more high-quality fish for local consumption. In a country that’s powered by fish — Bangladesh was the fifth-largest global aquaculture producer in 2018, according to the Aquaculture and Fisheries Journal — this technology could have profound implications for the economic power of fish farmers and the communities that rely on their labor.
The Feed the Future Innovation Lab for Fish (also known as the Fish Innovation Lab) has funded a research project that began in 2020 to develop cryogenic sperm banking of carp in Bangladesh. The project, implemented by the Department of Fisheries Biology and Genetics at Bangladesh Agricultural University, involves preserving and storing fish sperm cells, also known as “germplasm,” at extremely low temperatures, typically in liquid nitrogen, which maintains their fertility for future use. This allows researchers to store genetic material for long periods of time and maintain valuable genetic lines of fish species.
The need for this technology arises from deterioration of fish germplasm quality in government-run and private hatcheries in Bangladesh, explained M. Gulam Hussain, Fish Innovation Lab Asia regional coordinator. Inbreeding and other problems leads to fish that exhibit slow growth, high mortality and deformities. Continued production relies on improving the quality of broodstock, the “parent” fish used for breeding.
People in Bangladesh used to gather juvenile fish for breeding, called “fingerling,” directly from rivers, explained Madan Dey, chair of the Department of Agricultural Sciences at Texas State University, a project partner. Farmers did not face the same issues in river fish that they currently face in hatcheries. But now, collecting fingerlings from rivers cannot meet the needs of the growing population in the country, explained Dr. Dey. “That’s true all around the world, so we need aquaculture,” he said.
Cryopreservation technology can help address one of the problems facing hatcheries.
A man measures a length of cryopreserved sperm-originated rohu, a species of fish of the carp family, in Bangladesh. Photo credit: Mohammed Jahangir Alam/Feed the Future Innovation Lab for Fish
“This project is a bridge between what we used to do [gathering from rivers] and what farmers are doing recently [working in hatcheries]. We have the convenience of the hatchery but the quality of river stock,” said Dey.
The researchers have worked with 36 hatcheries in Bangladesh, and six-month sampling data compiled by the researchers revealed at least 20% higher growth rate of cryopreserved sperm-originated fish than those produced with hatchery-origin males, said Hussain. The shape, size and color of the cryopreserved-originated fish are better as well.
Rafiqul Islam Sarder, lead principal investigator for the project, said that 550 farmers have been trained on using the technology so far. Farmers in Bangladesh have spoken about how it has allowed them to turn more profit. One hatchery operator where the researchers conducted their work, Md. Anwar Hossain, said that better quality brood fish produce better quality offspring, which can result in high production and profits.
“If the hatcheries get cryogenic sperm easily, they may contribute [to the] national GDP [by] producing a huge quantity of better quality offspring,” Hossain explained.
This project, according to Feed the Future Innovation Lab for Fish Director Mark Lawrence, is dependent on the connection-building the team is doing.
“[This work] has tremendous potential to support improved genetics in aquaculture on a national scale because of the relationships the team has built with private hatcheries and nurseries to broadly distribute genetically improved carp to farmers,” he said.
The project is ending in September, but Dey said that the government of Bangladesh and Bangladesh Agricultural University have committed to “continue the legacy.” The Department of Fisheries, the main extension wing of the government, submitted a fish hatchery upgradation project to the Planning Ministry for approval, Dey explained. This proposal includes a section on setting up cryopreservation facilities in government hatcheries.
“It is not the end of the story. This is a technology that could be used for years to come,” he added.
The researchers are firm in their belief in this technology.
“Cryogenic sperm banking is the best technology to genetically improve the quality of broodstocks, which is the major concern for carp aquaculture in Bangladesh,” said Sarder.
In Bangladesh especially, that’s huge. As Hussain asserted: “Bangladesh is a fish-loving country. Our life without fish is impossible.”