I don't know if you have noticed that there are no giant predatory fish on the mainland, resulting in the proliferation of some exotic fish, such as: tilapia, scavengers, Egyptian pond fish and so on.
In the waters where these fish live, the indigenous fish populations on the mainland have been greatly reduced, so can we consider introducing a carnivorous fish with high food value and huge size to prevent the population of these exotic fish from spreading?
In fact, most people don't know that the mainland has introduced a giant fish, which not only has good meat quality, high edible value, and fast growth rate, but it is not necessarily effective to expect them to control the populations of invasive fish such as tilapia and Egyptian pond catfish.
Take Lake Victoria as an example, there is a fish in Lake Victoria that attracts thousands of anglers every year to go fishing, because there is a fish that grows in the lake, and this fish can weigh hundreds of pounds, what kind of fish is this?
Lake Victoria is located in the East African highlands, most of which are in Tanzania and Uganda, and a small part belongs to Kenya, with an area of 69,400 square kilometers, it is the largest lake in Africa and the second largest freshwater lake in the world, with an average water depth of 40 meters and rich fish resources.
However, the world's second-largest freshwater lake can't help but "cry"! The lake Victoria ecosystem has been nearly collapsed by the entry of one fish: the Nile barramundi.
In 1954, in order to develop the fishing industry, the hateful British colonizers introduced the Nile barramundi into Lake Veroria.
According to statistics, when the Nile barramundi did not enter Lake Victoria, there were hundreds of species of fish in the lake, and since the Nile barramundi entered Lake Victoria, more than 200 species of fish have been extinct in the lake! So it has become a "nightmare" for native fish!
So what is the Nile barramundi? Could it be that no one has a way to deal with this kind of fish that is eaten so much in Lake Victoria? Don't worry, let's talk slowly.
The Nile barramundi is native to Africa and is found in Lake Chad, Congo, Nile, Senegal, and Lake Turkana. It is the largest member of the barramundi family and is also the largest member of the freshwater fish of the order Perch.
They can reach up to two meters in length and weigh more than 200 kilograms, and because of the slight arching of their backs, they are also known as "King Kong", or "Bulging King Kong", why can they flood Lake Victoria? There are three main reasons for this.
1. Not picky eater
As long as any fish is widely distributed, then it has a characteristic, that is, it is not picky eater, and eats whatever it encounters. For example, carp, grass carp, crucian carp, etc., which are among the mainland carps, can be found almost all over the country.
The same is true for the Nile barramundi, except that it is a carnivorous giant fish that feeds mainly on other fish and is able to swallow up to a third of its own body length thanks to its large mouth.
2. Fast growth rate
Barramundi grows very fast, and mainland Guangdong, Hainan and other provinces introduced barramundi seedlings in the late 70s of the 20th century. Under natural conditions, barramundi live in fresh water and can grow to 3-5 kg in 2-3 years, with a rapid growth rate.
However, it is not tolerant to low temperatures, and when the water temperature drops below 15°C, it decreases or stops feeding, and when the water temperature drops to 10-13°C, it dies. In the coastal areas of Guangdong and Guangxi, frostbite and freezing to death of farmed barramundi often occur in winter.
3. Strong reproductive ability
Barramundi is extremely reproductive, and the number of eggs it bears is related to its weight. A female weighing 5.5 kg with 2.7 million to 3.3 million eggs and a female weighing 8.1 kg with 2.1 to 3.8 million eggs and weighing 22 kg has 17 million eggs.
It is not difficult to see from here that it has a super reproductive ability, weighing 22 kilograms, and the number of eggs can reach an astonishing 17 million, which is also a staggering number according to the survival rate of 10% in the natural state.
It is not difficult to see from here that the barramundi can dominate Lake Victoria, and it is not a picky eater, fast growth and strong reproductive ability, these three factors make the lake Victoria's native fish unable to compete with it.
Since the barramundi settled in Lake Victoria, its lack of natural predators has attracted many anglers to fish, and Lake Victoria has become a paradise for anglers for a long time.
According to a fisherman in Uganda, "I used a shark hook, hung 10 pounds of bait, and then tied the string to a tree with a 400-pound string, and on the second day the tree and the line were gone." (1 pound equals about 0.9 pounds)
Barramundi has been introduced into domestic farming, and some people want them to live in natural waters to control the populations of tilapia, Egyptian pond catfish, etc., but can this idea be realized? I find it difficult for three reasons.
1. It is not resistant to low temperatures
Barramundi is not tolerant to low temperatures, and when the water temperature is below 15°C, it will stop feeding, and when the water temperature is lower than 13°C, it will suffer from frostbite or even freeze to death, which limits its distribution.
In the coastal areas of Guangdong and Guangxi in mainland China, frostbite and freezing to death of farmed barramundi often occur in winter. It is not difficult to see from this that even the coastal areas of Guangdong and Guangxi are not allowed to safely overwinter and cannot be distributed on a large scale.
2. It's too edible
One of the drawbacks is that when barramundi was not introduced to Victoria Lake, there were hundreds of species of fish in the lake, and after the introduction, it turned the fish in the lake upside down.
Eating up more than 200 species of fish, this is not as simple as a big stomach, it should be said to be an ecological disaster, it is conceivable that if this fish enters the wild environment of the mainland, it will undoubtedly be a disaster for the native fish of the mainland.
3. There is no scientific basis
If you look at the performance of barramundi in Lake Victoria, this fish is not suitable for introduction at all, because it is so edible that it can eat more than 200 kinds of fish, and if it enters the mainland, it is estimated that all the fish in the water can be eaten!
The introduction of any fish needs a certain scientific basis, and the exotic fish we have introduced have already suffered the consequences. For example, the introduction of Egyptian pond catfish, which is really not eaten by anyone now; The introduction of scavengers is not eaten by anyone, and it has become a proper pest fish!
Finally: in fact, biological invasions can be seen everywhere, and there are more than 400 kinds of alien organisms that have invaded the mainland, which not only cause economic losses, but also cause irreparable harm to the local ecology.
Fortunately, the mainland has enacted legislation to prohibit the release of organisms that are not local, and "local" must be understood, which means that there are other places on the mainland, but if there is no local area, they cannot be released, and the release of alien species is strictly prohibited. In order not to cause harm to the ecological environment, protecting the environment is to protect our homeland.