Once upon a time, the fish in the river around me saw less, which made people worried. At present, with the gradual improvement of the water ecological environment, wild fish living in Beijing and its neighboring areas are slowly picking up.
In the middle of summer, the green tree-shrouded suburb of Beijing is slightly cooler than the urban area. Standing next to the Huaisha River, the shore breeze blows willows, and the open river surface is sparkling. Bowed, the crystal clear water of the river, from time to time there are toothpick-sized wild fry, swimming freely among the pebble aquatic plants.
The Huaisha River is an important river in the upper reaches of the Huairou Reservoir, passing from south to north through the oral village of Qiaozi Town. "In the early years, there were houses everywhere on both sides of the river." He Dongwei, deputy secretary of the party branch of Koukou Village, grew up by the Huaisha River and witnessed every change here. "Because of its proximity to the Huairou Reservoir, in the past, many villagers set up small courtyards in the open space on the bank of the river, and more than a dozen interception dams have appeared in the river channel to raise fish in enclosures for tourists to fish." The river is locked by a series of self-built interception dams, the water cannot flow, and the water quality is getting worse and worse every day. ”
In recent years, with the three important rivers in the upper and lower reaches of the Huairou Reservoir, the Huaisha River, the Huaijiu River and the Yanqi River, the aquaculture industry has been completely withdrawn, the dams and dams have been dismantled and the private construction on both sides of the river has been dismantled, and the silt at the bottom of the river has been cleaned up. "The water has flowed, and the ecology has changed significantly." He Dongwei was delighted to find that the "white striped" fish and "milk bun" fish that were common in the Huaisha River when he was a child had swam back after many years.
Big-tipped carp
Dotted silver bass
In the Aquatic Wildlife Nature Reserve between the Huaijiu River and the Huaisha River, Zhao Yahui, an associate researcher at the Institute of Zoology of the Chinese Academy of Sciences and an expert in ichthyology, found through field investigation that the wild indigenous fish in Beijing are showing a rebound trend. "In 2004, we took students here to do a detailed survey once a month and collected 21 species of fish; in 2017, spring, summer and autumn were only visited once, and the investigation intensity was much lower than before, but we found 33 species of fish, an increase of 12 species compared with before, such as largefin carp, dotted silver catfish, stick flower catfish, northern loach, etc., mainly some common wild fish."
A similar situation also occurred in Mentougou and Yanqing, where the Yongding River flows. Zhao Yahui and the scientific research team, from 2016 to 2018, collected a total of 25 species of fish through fixed-point collection. This is an increase of 9 species compared to the data collected from 2002 to 2010, and the fish diversity of the Chaobai River Basin, which has been well protected by the water environment, has been maintained at a relatively high level for more than a decade.
From 2002 to 2010, Zhao Yahui conducted continuous field surveys and collections of wild fish in and around Beijing, combined with fish specimens collected by the National Zoological Museum of the Institute of Zoology of the Chinese Academy of Sciences, to calculate that before 1930, there were 85 species of native fish in Beijing – which was also the period when Beijing had the largest number of fish species, surpassing the sum of all freshwater fish species in Europe. By 2010, it had dropped to 41 species, and nearly half of the native wild fish species had disappeared.
In the past two years, Zhao Yahui has seen gratifying changes. "Fish are an important part of aquatic ecosystems, and the diversity and spatial distribution of fish can reflect the quality of water bodies to a large extent." Zhao Yahui told reporters, "Beijing has alleviated the shortage of water resources through a series of measures such as the south-to-north water diversion and the introduction of yellow into Beijing. Relevant authorities are also paying more and more attention to water protection, water treatment and other issues. The data shows that beijing's ecological environment water consumption is rising every year, and ecological water consumption is second only to domestic water. ”