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More and more Small South American fish such as mosquito-eating fish, garnets, anglerfish, and red-tailed headguards are "doves occupying the magpie's nest" and occupying the territory that originally belonged to the "indigenous fish" in Jiangnan. Recently, at the expert demonstration meeting on the overall plan for the census of aquatic wild animal and plant resources in Jiangsu Province held in Wuxi, it was reported that Jiangsu will use 3 years to carry out a comprehensive census of offshore and freshwater aquatic wild animals and plants in the province. In this census, the fish resources of rivers and lakes will be surveyed, and even some small rivers in Wuxi have been included in the scope of the survey, and fish the size of small fingers such as mosquito-eating fish are the subjects of investigation.
Native fish are no match for foreign "strong dragons"
"Mosquito-eating fish from South America have been found in some small ditches in the southern Jiangsu region. Correspondingly, there are fewer and fewer medaka, which are homegrown and grown. According to the relevant staff of the Freshwater Fisheries Research Center, from 2009 to 2012, the Institute of Aquatic Sciences of the Chinese Academy of Sciences in Wuhan and the Nanjing Institute of Environmental Sciences of the Ministry of Environmental Protection have done special surveys, including the investigation of fish resources in small rivers in southern Jiangsu.
Don't look at the mosquito-eating fish is small, but the survivability is extremely strong, can grow in a harsh environment, and reproduces very quickly in the waters of our province. Medaka and mosquito-eating fish have similar appearance and similar habits, both feed on plankton, and the increase in mosquito-eating fish will reduce the number of medaka. Medaka has become an endangered fish species, and the invasion of exotic fish is the main cause. Mosquito-eating fish are entrained in imported ornamental fish and swim into the waters of Jiangsu, and after nearly two decades of breeding, the number has been considerable.
Although no mosquito-eating fish have been found in Taihu Lake, "rivers, lakes and seas are all interconnected water systems, and since mosquito-eating fish have been found in small rivers, the possibility of existing in the lake has not been ruled out", the researchers said, although no similar survey has been done, and less attention has been paid to the fish resources in the small river, but it is true that ornamental fish such as eels and red-tailed head-guard crucians have been found in the lake, and most of these fish are exotic species from South America.
In the past half century, the variety of fish in Lihu Lake has halved
In recent years, in addition to the changes in the fish resources in the small rivers, the fish resources in the lakes have also quietly changed. Wuli Lake, also known as Li Lake, is an inner lake where Taihu Lake extends into Wuxi City, and is a shallow water lake. Before 2002, Wuli Lake belonged to the aquaculture lake, and the lake management generally adopted the method of spring stocking of fish species and winter large-scale fishing; after 2002, Wuli Lake began to implement "endogenous governance", its functional positioning was tilted towards the natural lake, and the dominant position of the "four big fish" that was artificially stocked in the past was gradually weakened. "In the 1950s and 1960s, the Institute of Aquatic Sciences also conducted a survey of fish resources in Wuli Lake, and I remember that there were more than 100 species of fish at that time." According to researchers at the Institute of Aquatic Sciences, these hundred or so species of fish are "indigenous fish", and there were almost no invasive alien species at that time.
From 2007 to 2011, Wuxi conducted a survey of the fishery resources of Lihu Lake, and surveyed the fish community structure of the lake. At that time, 10 monitoring stations were set up in Wuli Lake, a lake in the northern part of Taihu Lake, and the 10 sampling points were Fisherman's Island, Luding Mountain, Chongshan, Mingyue on the Water, Baojie Bridge, Shuanghong Garden, Zhenbaofang, Meihu, Xishi Island and Shitang Bridge. In this survey, a total of 40 species of fish were collected in Wuli Lake, belonging to 6 orders and 10 families, of which the carp family is the mainstay, with a total of 29 species, accounting for 72.5%.
More than a dozen exotic fish have been found in Taihu Lake
At that time, there were two kinds of exotic fish in Wuli Lake, the anglerfish and the sparrow, of which the angler fish originated in South America, also known as the "scavenger", mainly eating scavenger crumbs, but also eating the eggs of native fish; the gar is produced in North America, is a ferocious type of fish, with sharp teeth, will attack other fish. "Although these two kinds of fish were not collected at that time, in order to prevent the invasion of alien species from intensifying, the fishery administration department was still reminded to strengthen the legal publicity of nearby residents, increase the residents' awareness of environmental protection, and let residents further understand the ecological harm caused by the arbitrary release of alien species," revealed the researchers who participated in the survey that year, "On the other hand, propaganda, while carrying out artificial release, we must also pay attention to avoiding the mixing of alien species, and try to choose fry, snails and river mussels from the seed farms in the Taihu Lake Basin."
Not only that, Taihu Lake monitors have also found gar in Taihu Lake. This large and fierce fish, in addition to humans have no opponents, the fish in Taihu Lake can become its belly. At present, more than a dozen kinds of exotic fish have been found in Taihu Lake. "Exotic fish are mainly ornamental fish in tropical areas such as South America, in fact, there are colorful ornamental fish in the Yangtze River." According to the researchers, the native fish such as the trout and the color pair in the Yangtze River are colorful and very beautiful, and their ornamentality is no less than that of exotic fish species. The indiscriminate selection of released varieties increases the threat of alien species to the indigenous ecology.
According to the staff of the Freshwater Fisheries Research Center of the Chinese Academy of Fishery Sciences, from the monitoring situation in recent years, the main exotic species of fish in Taihu Lake are mosquito-eating fish, red-tailed head-guarding carp, mirror carp, spoon-sturgeon, scavenger, etc. These fish species will compete with native fish for food, space and even mate competition, resulting in impure fish species and mixed genes of freshwater fish in Taihu Lake, which will affect the biological balance of Taihu Lake for a long time. "These exotic fish are mainly brought in by the public." To this end, the staff of the research center reminds that it is necessary to consult the fishery authorities before release, and the selection of released fry should also consult expert opinions.
The provincial census is about to begin
"The province is also concerned that fish stock species are changing." Relevant people from the agricultural department of Wuxi said that the overall plan for the census of aquatic wild animal and plant resources in our province has been approved by experts at present, and the census will be launched next month. In the next three years, Jiangsu will conduct a comprehensive census of the province's offshore and freshwater aquatic wild animals and plants. This is the first census of aquatic biological resources in our province in the past 40 years, and it is also the first time that our province has investigated the number and distribution of aquatic animals and plants. In this census, small fish the size of small fingers such as mosquito-eating fish and medaka are also surveyed.
This census will have a set of special technical specifications and operating procedures. "This census strives to investigate all varieties completely." Participants in the survey said that the census workload is very large, and the time span of the project is 3 years. The first survey results are expected to come out as soon as this year.
Our province plans to enact legislation to say "no" to release
In addition to the census, the legislature has also begun to focus on "the damage caused by release to the natural environment". It was learned from relevant departments that at the 23rd meeting of the Standing Committee of the Twelfth Provincial People's Congress held recently, the Regulations on the Protection of Wetlands in Jiangsu Province (Draft) (hereinafter referred to as the Draft Regulations) were deliberated in advance. For the release activities that have caused a lot of noise in recent years, the Regulations (Draft) clearly say "no".
It is understood that in 2015, the "Jiangsu Provincial Wetland Protection Plan (2015-2030)" was issued with the consent of the provincial government, and after a series of preliminary preparations and research, on the 28th of last month, the 84th executive meeting of the provincial government discussed and passed the "Regulations (Draft)". Jiangsu intends to legislate to protect 2.822 million hectares of wetlands in the province, and in the future, if it engages in activities such as reclamation( reclamation, landfilling, sand digging, soil extraction, mining, pond digging, burning, fishing, etc., in the wetlands, it may be fined less than 100,000 yuan.
According to Article 36 of the Draft Regulations, unless otherwise provided by laws and regulations, it is prohibited to engage in the following activities in wetlands: the introduction of alien species or the release of animals, the destruction of wildlife habitats and fish migration channels, the hunting of wild animals, the collection of bird eggs or the collection of wild plants, the capture of fish or other aquatic organisms, etc., in violation of this provision may be punished by a fine of up to 100,000 yuan. (Picture from the Internet) Evening News reporter Yuan Xiaolan/Wen
Link: Mosquito-eating fish
Native to the North American river bay, it was introduced to China by the Philippines in 1924.
Mosquito-eating fish are very adaptable, can live in the environment of water temperature 5 °C-40 °C, like to swim in groups on the surface of the water, agile action, is a fetal fish. Mosquito-eating fish generally feed on aquatic invertebrates, especially mosquitoes and mosquito larvae. Because it has no stomach, the digestive tract is thick and short, it can be described as wolfing when predation, it can be eaten with an upturned mouth to eat the mosquito larvae close to the water surface, Guangdong once introduced this fish to the wild in the 1960s, and the mosquito control effect is remarkable. According to statistics, each mosquito-eating fish can swallow 40-100 mosquito larvae in a day and night.
Mosquito-eating fish were introduced in Hong Kong and Taiwan in the early years, but later species such as the local medaka were affected. Mosquito-eating fish are listed as one of the world's top 100 invasive species by the IUCN for competing with native fish everywhere and disrupting the ecological balance. In Australia, the huge competition created by mosquito-eating fish for local fish and frogs is believed to be responsible for the extinction of rainbow fish in subtropical rivers near Brisbane.