Speaking of sunfish, many people may not have seen or even heard of it, because this fish is not a native fish in china, but a freshwater fish from the southern united states and northern Mexico.
Sunfish is an invasive alien species, originally did not intersect with us, but recently There is a reaction from Sichuan anglers, in the local natural waters, half a day caught dozens of pounds of sunfish, these fish are not small, the large ones weigh 1 to 2 pounds.
According to local anglers in Chengdu, Sichuan, not only are there a large number of sunfish in Chengdu's natural waters, but even reservoirs, rivers and lakes in other parts of Sichuan have been invaded by sunfish.
The director of the Fishery Administration Department of the Sichuan Provincial Fisheries Bureau confirmed that there are indeed alien species of sunfish in the natural waters of Sichuan Province, but from the current development trend, it will be difficult for sunfish to be "anti-guest-oriented" for a while and a half.
However, everyone can not take it lightly, although the sunfish is not very large, in fact, the sunfish is a "fierce character". Japan was once invaded by the sunfish, and finally launched a national extermination of fish, but the sunfish's most fatal weakness is that it has fewer thorns and tender flesh, and it is difficult to become a climate in the end.
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Sunfish are native to lakes and rivers in the southern United States and northern Mexico, as well as in the freshwater waters of Ontario and Southern Quebec in Canada. Sunfish are small and medium-sized fish, with a maximum growth length of about 30 to 40 cm, but its species are more diverse, with about 30 species.
Most of the sunfish that invaded Sichuan are Lansi sunfish, and the common size of this sunfish is about 100 grams, and the maximum can grow to about 2 to 4 pounds. Many people wonder why foreign fish can survive in The waters of Sichuan in China and multiply in large quantities.
Because the sunfish has a very strong ability to adapt to the environment, especially its temperature adaptability, it can live at a water temperature of 1 to 38 ° C. When the water temperature is below 8 °C, or above 38 °C, the sunfish will stop growing.
However, it does not pose a threat to it, because sunfish can safely overwinter at water temperatures of 2 to 3 ° C. Sunfish are omnivorous fish, feeding is divided into two stages, in the juvenile stage is mainly based on the larvae of mosquitoes, branches, copepods as a diet.
The feeding habits of sunfish will change after growing up, at this time, it is mainly based on eating small fish and shrimp, and has the nature of aggressive fish, which is very similar to the habits of tilapia to be precise, so it is also a high-risk invasive species.
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Although the sunfish invading the waters of Sichuan will not cause much harm in a short period of time, if it is not prevented, once it forms a large population, it will be difficult to detect the bottom and eliminate, and it will also bring disasters to native fish.
The reason why the sunfish can flood in foreign countries is not only because of its aggressive predatory habits and the threat of lack of natural enemies, but more importantly, the sunfish has a strong reproductive ability and the sunfish's egg hatching rate is extremely high.
During the spawning season, male sunfish have a nesting habit, and after waiting for the female to spawn, the male will remain around the eggs until the eggs hatch into baby fish.
In addition, the growth rate of sunfish is also very fast, and the sunfish fry hatched that year can grow to about 500 grams in half a year in an environment with sufficient food. And these fry of the year, growing to about 150 grams, can reach sexual maturity and can reproduce again.
The breeding cycle of sunfish is very long, from March to October every year, during which they can breed 3 times. At this rate of reproduction, if there is no threat of natural enemies, the entire waters will soon be occupied, and Japan once paid a greater price.
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The sunfish first entered the freshwater waters of Japan in 1960, when the Mayor of Chicago gave the sunfish as a gift to Emperor Akihito and brought it back to Japan during a visit to the United States by Emperor Akihito (then Crown Prince).
Since I tasted sunfish during my visit to the United States and felt good, I transferred them to the Fisheries Research Institute for experimental domestication and breeding. The first to breed more than 1,400 sunfish were released to Lake Biwa and other waters in Japan between 1963 and 1964.
At first, the Japanese emperor was also well-intentioned and wanted to "add dishes" to the people, so at that time the fish was also called "prince fish". But what he didn't expect was that the sunfish were too fertile, and while grabbing the living space, they also ate other fish eggs and fry, which led to an ecological disaster!
By 2000, sunfish were almost everywhere in Japan's freshwater waters, and some people even found that the Moat of the Tokyo Imperial Palace had become the "territory" of sunfish, almost forcing Japan's "pet fish" salmon to a dead end.
To this end, Emperor Akihito said: "At that time, I wanted them to become a food, and now the situation makes me feel very sad. ”
Pomfret
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Sunfish first entered China in 1987, when it was introduced by the Chinese Fisheries Society from abroad for trial culture in Beijing and Hunan, respectively, and the Hubei Fisheries Research Institute also introduced sunfish fry from the United States that year.
With the success of domestication, sunfish have been introduced to Dongguan, Shunde and other places for artificial breeding. Due to the advantages of fast growth, high reproduction and strong disease resistance, sunfish were raised as an economic fish at that time.
Due to management negligence during the feeding process and the flood overturning the breeding pond, the sunfish escaped to the natural waters, but this does not rule out the release of someone, but it is certain that the sunfish have adapted to the natural waters of our country and can reproduce on their own.
In September 2015, two PhDs from Anqing Normal University, when assessing the health of the aquatic ecosystem in the Weihe River Basin near the Dabie Mountains, found a group of fish species that resembled "crucian carp", but these fish would swallow other eggs and juvenile fish, and then after research, these fish were found to be sunfish.
Although sunfish have been found in many parts of China's waters, but so far there is no flooding trend, the main reason is that the sunfish fish meat is tender and delicious, while the fish bones are still very small, and the fish meat is rich in nutrients, is a kind of edible fish suitable for all ages.
If you think about it, if such a delicious sunfish wants to be flooded in any part of China, you must first ask the local "foodies" whether they agree. Moreover, sunfish are of medium grade among freshwater fish, even higher than the price of crucian carp, and their price is stable at about 20 yuan a catty.
Sunfish steamed eggs
So far, since the invasive alien species entered China, except for the scavenger and the Egyptian pond mackerel, the rest may not be enough to eat, and crayfish is a typical example.
However, I would like to remind everyone here that if you catch these exotic species, it is best not to release them in pity, otherwise you will become the next scavenger!