To combat mosquitoes flooding Australia, the Australian government has introduced a fish to the United States that can eat mosquito larvae. However, after the fish was introduced to Australia, which lacked natural enemies, not only did not eliminate many mosquitoes, but instead hunted the native species, and even one frog died out. The Australian government was so upset that it even legislated in the heavily flooded states of Queensland and South Wales to ban the stocking and transport of the fish.
Australian mosquitoes
What fish is it that can give the Australian government a headache? Why is it an invasive alien species? Can it really help kill mosquitoes?
<h1 class="pgc-h-arrow-right" data-track="5" what kind of fish is causing headaches for the Australian government >? </h1>
The Australian government introduced mosquito-eating fish, native to the Guadalupe River in Texas, USA, and has been introduced by many countries as an important mosquito control measure because it feeds on the larvae of mosquitoes. Mosquitoes are a particularly resentful insect because they can transmit a variety of diseases by biting humans. Dengue fever, malaria, etc. are all transmitted on a large scale through mosquitoes in the population.
The U.S. government multiplied in large numbers in the early 20th century to control the mosquitoes that flooded the United States. The history of the introduction of mosquito-eating fish in China can be traced back to 1911. In order to combat the infectious diseases caused by the ravaging mosquitoes, the Taiwan government ordered 600 mosquito-eating fish from Hawaii to be transported into Taiwan via Yokohama, Japan, and only 126 mosquito-eating fish survived. Although the survival rate is low, the 126 mosquito-eating fish have multiplied on a large scale after gaining a foothold in Taiwan, and the number has greatly expanded.
Mosquito-eating fish that eat mosquito larvae
In 1924, the Philippine Institute of Medical Sciences donated a batch of mosquito-eating fish to Shanghai, and two years later the U.S. Department of Agriculture also donated a batch of mosquito-eating fish. Because of the adaptation of the environment, the donated mosquito-eating fish were bred on a large scale in small rivers and ponds on the outskirts of Shanghai, and began to be promoted in southern China's provinces in the 1950s. By the 1960s, mosquito-eating fish had successfully bred in Guangdong Province.
<h1 class="pgc-h-arrow-right" data-track="8" > mosquito-eating fish are mosquito busters</h1>
Mosquitoes have the ability to fly, how can aquatic mosquito-eating fish destroy it? To answer this question, we must first understand the living habits of mosquitoes. Although the adult mosquito does not live in water, it has three forms of life that are soaked in water. Mosquitoes have four forms, divided into eggs, larvae, pupae, and adults, from small to large. The common flying mosquitoes in our daily lives are the adult insects of mosquitoes.
The four stages of mosquitoes
To kill mosquitoes, it is best to start with its first three forms. Because it can only move in the water, it does not yet have the ability to fly. Because of this, mosquito-eating fish can prey on mosquito larvae in large quantities. Female mosquito-eating fish can eat five hundred mosquitoes a day at most, and at least a hundred.
How much do mosquito-eating fish contribute to the elimination of mosquitoes? In 1925, the Soviets introduced mosquito-eating fish through Italy, hoping to alleviate the flood of mosquitoes in the Soviet Union with the help of mosquito-eating fish. The introduction of mosquito-eating fish controlled malaria in the tourist city of Sochi in the southern Soviet Union in the 1930s, because malaria was mainly transmitted by mosquitoes. In recognition of the important contribution of the mosquito-eating fish to the fight against the malaria epidemic, the Soviet government specially erected a bronze statue for it in Sochi as a memorial.
Bronze statue of a mosquito-eating fish
<h1 class="pgc-h-arrow-right" data-track="12" > mosquito trap is an invasive species</h1>
Despite its name, it is not a full-time mosquito killer. This is because it is an omnivorous fish and eats a huge amount of food. Mosquito-eating fish have many aliases, such as wicker fish, big belly fish, pit fish, big-eyed stinging, bald-headed woman and big belly. Personally, I think that the "big belly fish" is more reflective of the characteristics of mosquito-eating fish, because it is so fond of eating.
Mosquito-eating fish are particularly large in food and can eat 42%-167% of their body weight. And it is not picky, as long as it is smaller than its small fish and shrimp it can swallow into the stomach, even larger than its fish will be nibbled a few bites. Mosquito-eating fish are cruel by nature and have a strong desire to attack. Wounds of large fish bitten by mosquito-eating fish can be infected with bacteria and fungi, and if no one saves them, they generally don't live long.
Fish that eat mosquito larvae
Mosquito-eating fish also eat mosquito larvae, but it doesn't really like to eat it, just seeing it as an alternative when there is no food. This led to an embarrassing phenomenon: originally wanted to introduce mosquito-eating fish as a natural enemy of mosquitoes, it turned out that this "tai nian ye" not only did not catch mosquitoes well, but caught small fish and shrimp in the pond to eat. Under the waste of mosquito-eating fish, the number of many species of fish and shrimp has been greatly reduced, and it has become the new hegemon of the pond itself.
Mosquito-eating fish not only eat a large amount, but also have a weak reproductive ability. Although the body of the mosquito-eating fish is particularly small, 15-40 mm long, only a few individuals are longer than 40 mm. But as the saying goes, "although the sparrow is small, it is complete", and the mosquito-eating fish has a perfect reproductive system in its body. Unlike other fish, mosquito-eating fish are fetal raw fish, which greatly improves the survival rate of mosquito-eating fish pups.
5 cm long mosquito-eating fish
Male mosquito-eating fish are much smaller than females, and people who do not know how to eat mosquitoes may see them as mothers and children when they see their body size comparisons. The fin of male mosquito-eating fish evolved into a sexual organ through which it transports sperm to female fish. Female mosquito-eating fish during the breeding season do not show favor to male mosquito-eating fish, but choose another form of courtship. Before mating, several male mosquito-eating fish follow the mother mosquito-eating fish and choose the mate of the female mosquito-eating fish by fighting.
The battle for the courtship of the mosquito-eating fish is very fierce, and only ends when the only winner of the suitor is generated, and the rest leave or die on their own. The winner can accomplish his mission. Of course, don't think that a successful mating male mosquito-eating fish is safe, and female mosquito-eating fish especially need food when pregnant. They will eat their mates like black widow spiders when there is no food. Without a mate, female mosquito-eating fish can also give birth. This is because female mosquito-eating fish will keep the sperm of the male fish in the body and use it when needed.
Comparison of male and female mosquito-eating fish
Female mosquito-eating fish that have completed mating will give birth to hatched pups from their sexual organs, and can produce 30-50 small fish at a time. Female mosquito-eating fish, on the other hand, can breed 3-7 times in a lifetime, producing 90-350 small fish. Because of the large reproduction, female mosquito-eating fish do not care for their cubs, but will eat their cubs when they are extremely hungry. Even their own cubs do not know how to cherish, naturally do not know how to respect the lives of other creatures.
In addition to eating a large amount of food and strong reproductive ability, mosquito-eating fish also have an amazing ability. That is, the environmental adaptability is excellent. Mosquito-eating fish originate in the subtropics, but are found except in the northern parts of the northern hemisphere. Mosquito-eating fish can ensure their survival by adjusting the fat content in different regions and different seasons, and the body fat rate of mosquito-eating fish will be higher in the northern latitude or cold season; and the body fat rate of mosquito-eating fish in the southern latitude or warm season will be lower. The environmental adaptability of mosquito-eating fish can be seen.
Origin of mosquito-eating fish
In addition to being extremely adaptable to the environment, mosquito-eating fish can also survive in some heavily polluted ponds and lakes. Mosquito-eating fish can survive in strong acids and alkalis that ordinary fish cannot survive, as well as in almost anaerobic water, and can also survive in 3% concentration of brine.
It is precisely because of the strong aggression, large food intake, strong reproduction and terrifying environmental adaptability of mosquito-eating fish, coupled with the reason of artificial introduction, that it has been recognized as an invasive alien species by many countries.
Caught mosquito-eating fish
<h1 class="pgc-h-arrow-right" data-track="20" > making it more difficult to handle mosquito-eating fish</h1>
As the saying goes, "It is easy to ask God to send God to be difficult." In order to deal with the introduction of mosquito-eating fish by flooded mosquitoes, it is too late to think about how to deal with it until it has gained a foothold and caused serious damage. Australians, who are not lightly tortured by mosquito-eating fish, have thought of many ways to deal with it, such as draining the water from the pond where it inhabits, putting insecticides into the water body, and so on. However, this is all a sinister move to kill a thousand enemies and damage eight hundred, and the effect is not great.
Since you can't poison them, you can eat them, right? I'm sorry, but mosquito-eating fish are small and prickly, so I can't eat fish at all. Although the amount of food eaten by mosquito-eating fish is particularly large, because of the digestive organs, many foods are directly excreted from the body after rough digestion and are not converted into fat. Take it as an ornamental fish, think about the sins it has made, and you are not in the mood to watch it.
Some of the mosquito-eating fish are very beautiful
What is even more ironic is that although it is called a mosquito-eating fish, it is reluctant to prey mosquito-eating fish with other prey. Australians who introduced mosquito-eating fish found that mosquito-eating fish prey on mosquitoes in much lower numbers than native fish. It can be said that the global large-scale introduction of mosquito-eating fish is a particularly serious misstep.
<h1 class="pgc-h-arrow-right" data-track="23" > conclusion</h1>
From the case of mosquito-eating fish, it is not difficult to find that the introduction of alien species is not an easy task. Be cautious about the introduction of alien species for any purpose!