Editor’s Note: As coverage of the planet’s flora, fauna and resources becomes important, China Daily publishes a series of articles to illustrate the country’s commitment to safeguarding the herb world.
The once-murky waters of the lakes and reservoirs of northeast China’s Liaoning province have become transparent thanks to the help of a spouse discovered in Mother Nature: fish.
The Liaoning State Water Resources Management Group began implementing a plan put forward by the then Ministry of Agriculture in 2016 to identify fish farms in algae-infested water bodies to ensure water quality and provide a secondary source of income.
Algae blooms occur when nitrogen and phosphorus accumulate in lakes, reservoirs, and other slow-flowing waters due to agricultural runoff and pollution from untreated urban wastewater.
Blooms endanger the ecosystem of freshwater lakes and can lead to odor alterations in drinking water.
The water monitoring group, which manages 16 reservoirs in Liaoning and supplies about 70% of the province’s water, has long struggled with algae.
By introducing fish into water bodies, the water resource organization can stop algae blooms, clean the water, and then bring the fish back to market once it reaches maturity, generating a source of income and strengthening the country’s food security.
In recent years, provinces such as Yunnan, Anhui and Shandong, where freshwater lakes abound, have also implemented programs.
However, the officials in charge of these systems have warned that the procedure is as simple as it seems.
“Not all fish can thrive in tanks,” says Guan Wankai, who oversees the group’s operations at the Guanyinge Reservoir in Benxi, southeast of Liaoning.
Guan said that in order for the program to work, the organization screened filter feeders, carp and catfish, which swallow waste suspended in the water.
He explained that the fish in the Guanyinge reservoir are basically silver carp and bigheads.
Citing data from studies, the official said that harvesting one kilogram of carp is equivalent to removing about 20 grams of nitrogen, 1. 5 grams of phosphorus and 118 grams of carbon from the water. Calculated based on algae biomass, 40 kilograms are removed. of water for each kilogram of fish caught.
In a written reaction to the China Daily’s request for comment, the organization said it released 7,945 tonnes of carp and species in Liaoning last year, with the harvest amounting to 28,100 tonnes.
In 2023, 4,600 fish were caught, and the organization raised another 71 million yuan ($9. 86 million), according to the statement.