Years ago, ponds in Helan county were barren saline-alkaline marshes. Now many marine products, including freshwater fish, are being raised across a myriad of fish farms in the county in the Ningxia Hui autonomous region.

The county government has found a new path to curb its saline-alkaline land to develop its economy through fishing, allowing the aquatic product farming industry to shine in the inland region.

According to Dong Yuehui, director of the Yellow River Economic Fish and Aquatic Germplasm Resources Field, more than 5 metric tons of rainbow trout and dozens of fish species, including carp, grass carp, mandarin fish and sturgeon, are being raised in 20 huge circular aquaculture farms in the field.

"It is the first time rainbow trout are being introduced for aquaculture in Yinchuan, capital of Ningxia. And in addition to Yellow River fish, we are trying to breed various new types of fish and shrimp in the field," Dong said, adding that giant freshwater shrimp have also been introduced for the first time this year.

In the beginning, the new varieties were raised in the farm's circular breeding pools for temporary cultivation, while controlling the circulating water through full automation to regulate the water temperature and oxygen content to ensure the growth rate.

"Now rainbow trout are gaining weight, with some fish weighing more than 500 grams, and can be sold," Dong said.

After October, a great deal of rainbow trout will enter local markets and arrive on dining tables, he said.

Many aquatic products raised in the field are also being sold in the Xizang and Inner Mongolia autonomous regions, and the provinces of Gansu and Qinghai, he added.

Located in Helan's Sishilidian village of Changxin township, the farm, which was built in 2021, mainly engages in the standardized reproduction, breeding and protection of the germplasm resources of Yellow River fish.

"The entire workshop has adopted a fully automated, factory-based water circulating aquaculture model, and the filtered fish manure and feed are transported to the rice fields to become bio-fertilizers. And through such circular aquaculture, water consumption can be reduced by 30 to 40 percent," he said.

Qiang Zuozhou, another executive in charge of the field, said Ningxia has a wide distribution of saline-alkaline lands that are suitable for raising aquatic products.

The soil salinization in the Yellow River irrigation area mostly belongs to the saline soil distribution type, with salinity ranging from 2 to 18, and pH values between 7.7 and 9.3.

The development of aquatic product farming has obvious advantages, making the taste of the fish, shrimp and crabs raised in Ningxia even more delicious, he said.

Also, the South American white shrimp has become the most successful domesticated aquatic product variety in Ningxia, he added. The annual output of South American white shrimp is expected to hit more than 60 tons in Helan this year, he said.

Raising fish and shrimp in saline-alkaline land not only revitalizes resources, but also has broad market prospects.

To further promote the development of "land-based aquatic products", fish farms in Helan have also optimized deep processing and extended the industrial chain, Qiang said. They are churning out fish balls and fish cakes, as well as pre-cooked vegetable production lines, he said.

Yu Fang, deputy director of Helan County Bureau of Agriculture and Rural Affairs, said the suitable aquaculture area in the county has remained stable at more than 38.66 square kilometers, accounting for 11.6 percent of the total in Ningxia.

"Helan's total fishery output is 63,500 tons, representing 30.6 percent of the total of Ningxia, helping build the county into a national demonstration zone for healthy and ecological aquaculture," Yu said.

"The county's total annual output value of fishery has reached 817 million yuan ($113.47 million), accounting for 15.9 percent of Helan's total output value of agriculture, forestry, animal husbandry and fishery, making it the largest county in terms of fishery industrial development in Ningxia," she added.

Yu also said that the breeding area of aquatic products in Helan is now more than 8 million square meters, accounting for 20.7 percent of the county's total fish farming areas.

The main varieties include South American white shrimp, largemouth black bass, spotted catfish and river crab.

Meanwhile, many sea fish and aquatic products, including large yellow croakers, green crab, mandarin fish, fragrant fish and spotted shrimp are also being raised in Helan, and they are all growing well, she said.

"The aquatic products from Helan are selling well not only in local markets, but also in Xi'an in Shaanxi province, Lanzhou in Gansu province and surrounding major cities, playing an important role in helping local farmers increase their incomes," she said.

To expand aquaculture, Helan will further deepen cooperation with multiple domestic aquatic research institutions and universities, and strengthen the scientific and technological innovation awareness of fishery breeding enterprises.

"Great efforts will be made to achieve technological breakthroughs in the breeding of saline-alkaline tolerant varieties and the research and development of specialized feed nutrition formulas for saline-alkaline water environments in the following months," she added.

Contact the writers at zhengcaixiong@chinadaily.com.cn