Protection of fish resources in the Guangxi section of the Pearl River Basin: fish recuperate and recuperate

The fish rested and recuperated

——Perspective on the protection of fish resources in the Guangxi section of the Pearl River Basin

On October 13, the "2016 Aquatic Wildlife Conservation Science Popularization Month" was launched in Nanning. Children learn about aquatic wildlife through puzzles on the spot. Reporter Yuan Lin/Photo

Guangxi News Network-Guangxi Daily reporter Yuan Lin Wang Chunnan

The Pearl River Basin is the cradle of guangxi's fish resources. Guangxi has more than 4,000 kilometers of rivers, and the Pearl River fishing ban period in Guangxi's fishing ban section is 2,010 kilometers long, accounting for more than half of the total length of rivers in the region.

On October 13, Guangxi launched the "2016 Aquatic Wildlife Conservation Science Popularization Month". The survival of fish in the Guangxi section of the Pearl River Basin has once again entered the field of people's attention.

The original fish have been sharply reduced

Invasive varieties flourish

"Among the common fish in the Yongjiang River, such as red stingray, light barbed catfish, barbed catfish, Guihua catfish, lip carp, long-rumped fish, etc., have rarely been recorded in recent years, and some species have not even appeared for more than ten years." Shi Jun, an engineer at the Guangxi Academy of Fishery Sciences, who has been investigating and studying the pearl river's fish resources for many years, expressed concern about the declining "indigenous" fish resources in the Pearl River basin.

Years of research by the Pearl River Fisheries Research Institute of the Chinese Academy of Fishery Sciences also confirm this statement – according to surveys in the 1980s, there are 385 species of fish in the Pearl River system, accounting for nearly half of the number of freshwater fish species in China. However, at present, there are 131 rare or invisible aquatic species in the middle and lower reaches of the Pearl River, accounting for about one-third of the total; Chinese sturgeon, anchovies, tang fish and other fish have become fish that have not been seen in the Pearl River for many years.

"The last time I saw Chinese sturgeon in the Pearl River was in 2003." Li Xinhui, a researcher at the institute, once told reporters that the Chinese sturgeon is a large river-tracing migratory fish, and the earliest discovery site is in the Pearl River. Chinese sturgeon can sail as far as the west coast of the United States to live, and whenever they spawn, they always have to return to the Pearl River Basin in Guangxi, and the migration journey is about 700 to 1000 kilometers. However, after the completion of many dams in the Pearl River Basin, wild Chinese sturgeon has not been found anymore, and now the government department releases artificially hatched Chinese sturgeon every year during breeding and stocking.

While "indigenous" species are declining, "exotic" species are thriving. Shi Jun listed more than 10 species of exotic fish found in the Yongjiang River, and said that "these species are not well-received, and they have carried out a genocidal invasion war, which has completely changed the original ecological environment." ”

The fishing ban has had limited effect

Governance depends on a combination of fists

The Pearl River Basin has been under a fishing ban since 2011, with fishing bans from April 1 to June 1 every year. The Nanpan River, Hongshui River, Qianjiang, Xunjiang River and Liujiang River (including Rongjiang), Guijiang River (including LiJiang) and Yujiang River (including Yongjiang River) in the upper reaches of the Xijiang River in Guangxi are listed as prohibited from fishing in 2010 kilometers.

Now 6 years later, a survey by the Guangxi Academy of Fishery Sciences shows that the fishing ban system has achieved initial results, and the quantity and quality of fish caught by fishermen have shown a trend of increasing and improving, but the effect is limited, and the two-month fishing ban period every year cannot cure the problem of depletion of fish resources in rivers. A follow-up survey of 59 fishermen for three consecutive years showed that these fishermen only caught more than 30 species of fish, less than one-third or even one-fifth of the fish recorded in each river section.

Researchers believe that the fishing ban system cannot change the problem of resource depletion caused by overfishing, if not controlled, once the fishing ban period is over, the fishing force will swallow up the fruits of the fishing ban. Secondly, there are more than 50% of the anthropogenic fish in the Pearl River Basin, as well as a large number of rapids fish, and the fishing ban system cannot solve the difficulties of river blockage and sparse fish parents, resulting in their natural proliferation.

It is understood that although some water conservancy hubs have built fish facilities - fish ladders, since the dam was intercepted, the time for the fish ladder to open the gate and release water is countless, so that the fish cannot "climb the ladder" and return to the original birthplace upstream to breed, resulting in the reduction and extinction of variety resources.

"Further strengthen the capacity building of fishery administration and water administration institutions, strengthen law enforcement forces and means, and strictly enforce and supervise." Experts recommend that the impact and damage of barrage dams and other hydraulic facilities on the ecological environment be minimized and the fishing ban extended. Shi Jun said that many fish have an spawning period of more than 6 months, and the fishing ban period is too short, which is not conducive to the natural proliferation of fish resources.

Scientific release and proliferation

Construction of fishery "special zones"

In the face of the unoppositive reality, in order to protect the "Mother River", the fishery administration department of our region, in addition to strictly implementing the policy of the fishing ban period in the Pearl River Basin, has also restored fishery resources by releasing and breeding suitable fish in the river. It is understood that in recent years, the fishery administration departments of the whole region have stocked silver carp, bighead carp, blue carp, grass carp, yellow jaw fish, red-eyed trout, slender-scaled slanted carp, mud carp and other fish into the Pearl River Basin every year, and the stocking volume has exceeded 10 million.

At noon on September 29, the reporter found that a tricycle with the words "release of raw fish fry" was parked on the yongjiang river in Nanning, and the owner put down seven or eight bags of aerated fish fry in one go; soon five or six people came, and they were the people who bought this batch of fish for release. It turned out that the "100-day release" activity was being carried out here, and these citizens would release them to the Yongjiang River once a day, and a total of 6,000 mud carp were prepared this time. They said that the released fry species will be screened and will not release exotic species such as the Brazilian turtle.

However, not all stockists know how to release fish scientifically. Mr. Huang, who was fishing by the Yongjiang River that day, said that he saw several young people carrying a bag of fish to the river to release, and "the mouths of the two fish are very long and very pointed." "It turned out to be an exotic species of garnet.

Native to North or Central America, the gar is a large, ferocious fish species that pose a great threat to other local fish species as an invasive alien species. So how to deal with these "outsiders"? Shi Jun gives the best advice: eat them all!

In addition to stocking and breeding, the construction of fishery nature reserves is also one of the most effective measures to protect fish diversity and its ecological environment. It is understood that the section of the river under the Dam of Changzhou, Wuzhou, with its unique geographical location and diverse hydrodynamic environment, is suitable for the spawning and reproduction needs of a variety of economic fish, and has become one of the main spawning grounds for eels, Guangdong bream and other fish; at the same time, it also inhabits 25 national aquatic germplasm key protected species such as flower eel, Japanese eel, red-eyed trout, bluefish, carp, and moon bream. Experts suggest that in the form of legislation, in the form of legislation, in the sub-dam section of each barrage dam in the Pearl River Basin, fish spawning grounds, and bait wintering habitats, demarcation of "fishery nature reserves" or "fishing ban areas", the establishment of corresponding management agencies for construction, management, and regular assessment of the effect.