Mosquitoes have always been a headache for us, not only do they sound disturbing, but they also transmit diseases, especially malaria is the most deadly, and mosquitoes are one of the main ways to spread malaria. But the emergence of mosquito-eating fish can make the mosquito population well controlled, so what kind of extraordinary ability does the mosquito-eating fish have to help us control the hateful mosquitoes? Mosquitoes can fly, how do they eat them?
Mosquito-eating fish are native to the United States, and later due to continuous breeding and spread, the distribution area has gradually become more extensive, and it has also appeared in the southern United States and Mexico. It is also known as the big belly fish in some areas, and some people also regard wheat ear fish and peacock fish as mosquito-eating fish, which are actually three different kinds of fish, but don't be mistaken. Mosquito-eating fish is a small size of fish, generally they will live in ponds, small lakes, rural reservoirs, swamps, farmland (generally paddy fields), small ditches and other areas, the water in these areas is generally static, not as fluid as most rivers, the reason why they do not survive in those areas with strong mobility, or because they are relatively small, in the static waters to be more suitable for survival and reproduction.
Not only that, but they also like to live together, usually living on the surface of the water. In terms of eating, when they are still in their infancy, they mainly prey on rotifers and ciliates, and when they are fully mature, they begin to prey on some insects and algae, especially like to prey on widows, that is, mosquito larvae. According to statistics, a mature mosquito-eating fish can eat nearly 2,000 birds a day. Therefore, in fact, the reason why mosquito-eating fish can control the number of mosquitoes is not because they eat mosquitoes that are already adults and can fly, but because mosquitoes are eliminated before they become adults.
Why can they prey on so many mosquito larvae?
This is because whether it is the living waters, or the level of survival in the waters, the areas where they live and the mosquito larvae are highly overlapping, and there are many areas where mosquitoes live, there are heavily polluted areas, there are static waters, and there are also rivers with strong mobility, but mainly static waters and polluted areas. And mosquitoes generally lay their eggs on the surface of the water, and after a period of time, the eggs will hatch into larvae. They also live on the surface of the water, swimming to eat algae and some other mosquitoes and so on. Therefore, the high degree of overlap between mosquitoes and mosquito-eating fish also allows mosquito-eating fish to prey on a large number of widows.
Because of this ability to prey on mosquitoes, mosquito-eating fish have long been introduced to various regions and countries to control the mosquito problem. Around the 20th century, mosquito-eating fish were farmed in North America as a mosquito control tool by the government departments of the time, and also spread to some parts of South America, the Philippines and other countries and regions.
In the process of governance, there is a very famous example: in 1925, the Soviet Union introduced mosquito-eating fish from Italy to control the mosquito flood at that time, and one of the cities, Sochi, was an area with a very serious mosquito problem. After the introduction of mosquito-eating fish, the local mosquitoes began to decrease dramatically. Therefore, Sochi built a statue of a mosquito-eating fish at that time to commemorate it and its exploits.
There are three main introductions of mosquito-eating fish in China.
The first introduction of about 600 mosquito-eating fish from Hawaii in 1911 was to Yokohama, Japan, and then to Taiwan. Most of the mosquito-eating fish also died on the way, and only the remaining 126 survived. However, because the climate in Taiwan is suitable for the survival of mosquito-eating fish, mosquito-eating fish will appear in Taiwan province soon after.
The second was in 1924, when the Philippine Institute of Medicine shipped some mosquito-eating fish to Shanghai for free for trial rearing.
The third time was in 1926, when the U.S. Department of Fisheries shipped another batch of mosquito-eating fish to Shanghai, and after a period of breeding, the mosquito-eating fish were bred on a large scale in Shanghai's ponds and ditches. Around 1960, it slowly began to spread to different parts of the north and south of China, and also carried out mass breeding, and is now mainly distributed in the southern provinces and cities.
The mosquito-eating fish is extremely reproductive, and its reproductive cycle is very short, and there are many juveniles produced at a time. Not only that, but newborn juveniles, if they live in areas with suitable water temperatures, can begin to breed for up to a month. The breeding period of mosquito-eating fish is very long, generally starting in April and ending around October, and can breed 3 to 7 times a year. Each breeding can produce about 30 to 50 juveniles, so combined, each female can produce 200 to 300 juveniles per year. Therefore, the reproductive speed and reproductive ability of mosquito-eating fish are extremely strong. And because it is an invasive alien species, there are not many natural enemies in the local area, which further increases its living space.
Mosquito-eating fish in shallow waters
Therefore, over time, its impact on the local ecological environment will become more and more obvious. Mainly reflected in the impact on native fish, because the mosquito-eating fish temperament will be more ferocious in comparison, so they will occupy the living space of other species. Among the fish that live indigenously in China, there is also a small fish that is very similar in appearance to the mosquito-eating fish, has a high degree of overlapping food sources, and will also prey on the widow, which we generally call the medaka. The two of them look very similar, so it is difficult for ordinary people to distinguish between the two and who is who.
Medaka
Medaka is oviparous, and after spawning, the eggs take a while to hatch, generally about ten days. However, mosquito-eating fish are fetal, and the eggs of mosquito-eating fish can be fertilized and grown in the female fish, and generally will wait until they grow up before they are discharged. In this way, the mosquito-eating fish is born with the ability to prey, its survivability will be improved, and the survival rate will be higher than that of the medaka. Not only that, but when the medaka is excreted, it is only a fish egg, if there are two kinds of fish in the same water at the same time, then the eggs of the medaka must be preyed on by mosquito-eating fish and mosquito-eating fish juveniles, resulting in a sharp decline in the number of medaka fish.
According to the observations provided by some old fishermen in Yunnan, around 1973, at that time, in the ponds and ditches along the Lancang River, you can still see medaka swimming back and forth from time to time, which shows that the number of medaka at that time was still quite large. However, around 1986, due to the large number of mosquito-eating fish entering the Yunnan region, the figure of wild medaka can no longer be seen near Jinghong, indicating that it has basically disappeared here. Not only small fish, even large fish, mosquito-eating fish will also eat the eggs of large fish, causing some trouble to the survival of large fish, but it is much smaller than smaller fish.
In addition to the Yunnan region, the exotic species of tilapia living in the Pearl River region have also been affected to some extent by mosquito-eating fish. As early as 2011, some researchers conducted scientific research on mosquito-eating fish living in the Pearl River region, and found that there were 3 partially digested tilapia juveniles in the digestive tract of a 24-centimeter-long mosquito-eating fish.
This discovery can't help but make people worry: if tilapia baby fish are also preyed on by mosquito-eating fish, then some domestic fish living in the Pearl River Basin will also have the possibility of being preyed upon, then their survival situation is also very bad. There may be some people who think that we can change this situation through artificial consumption, but in fact it is very difficult. The reason why mosquito-eating fish has no economic value is because it does not even have the value of eating. Mosquito-eating fish are often unclean things in the digestive tract, if not clean, eating will be very bitter, but if you really want to deal with clean, then the mosquito-eating fish will be left with the head to eat. And because its main food source is the malaria, the widow may carry the malaria parasite, and eating it casually is at risk of malaria infection. How do we think we should avoid the greater impact of mosquito-eating fish on our ecological environment?