Lead
On July 1, 2020, the Yangtze River officially entered a 30-year fishing ban, and two years after the implementation of the fishing ban, the fish resources in the Yangtze River have begun to slowly recover.
With the restoration of fish resources, it also represents the ecological restoration of the Yangtze River Basin.
Just as the number of finless porpoises photographed by the country in the past two years has increased from 1,012 to 1,249, and now the finless porpoise has become the "protector" of the Yangtze River.
According to the Yangtze River Protection Law issued in 2019, all exploitative fishing is prohibited in order to protect the ecological environment of the Yangtze River.
Since the implementation of the Yangtze River fishing ban, the Yangtze River's aquatic resources have recovered, and even fish that were once recorded as "extinct" have returned, such as the Yangtze River saury.
The decline of aquatic resources in the Yangtze River.
However, with the gradual restoration of the ecological environment of the Yangtze River, the Yangtze River has gradually returned to the ecosystem, but there are problems, and even more serious problems than the ban on fishing.
That is the invasion of alien species.
In fact, long before the implementation of the Yangtze River fishing ban policy in 2020, there were already 28 alien species waiting quietly in the Yangtze River, and even these 28 alien species have had a great impact on the ecology of the Yangtze River.
Therefore, although the fishing ban policy in the Yangtze River has achieved certain results, the problem of invasive alien species also needs my further attention.
So after the ban on fishing in the Yangtze River, what more alien species are in the Yangtze River?
The Yangtze River's aquatic resources have taken a sharp turn in the past few decades, from around 430,000 tonnes per year to less than 250,000 tonnes in 1995.
By 2017, before the Yangtze River was closed to fishing, it had dropped to about 100,000 tons, and it was only after the implementation of the Yangtze River fishing ban that the aquatic life in the Yangtze River recovered, but the rate of invasion of these alien species can be faster than that of fish.
In 2018, as many as 168 fish species were recorded in the Yangtze River Basin, and nine of them are national key protected species.
By 2022, 193 fish species had been recorded in the Yangtze River basin after the fishing ban was implemented in 2020, and 10 of these fish species were protected by the state.
This shows that the ecology of the Yangtze River basin has been slowly recovering, but it is also slowly increasing the danger, just like the aforementioned alien species are increasing year by year.
The number of alien species is slowly increasing and even slowly multiplying, which creates competition between alien species and native species.
Alien species of "alligator gar"
For example, in 2016, one of the "four pests" found in the southeast coastal area of the mainland, the alligator gar is an omnivorous invasive fish and an alien species that is extremely predatory.
In a very short period of time, several populations have been bred in the southeastern coastal areas of the continent.
And they will not only kill native fish, but also other animals.
And even the species that threatens them the most, the Chinese soft-shelled turtle, is almost extinct by predation.
In general, they can only lay eggs once or twice a year, and each time they can lay two to three hundred eggs, and they are extremely reproductive.
They do not stop reproducing even in winter, they can burrow under the surface of the water to lay eggs because they produce a special substance called "transparent protein" inside their oocysts.
The formation of this transparent protein is similar to the condensation process of hot springs and water vapor, which can protect against the cold and prevent the eggs in the egg sac from freezing in the cold.
The existence of the "alligator gar" species in the southeast coastal area of the mainland has caused a great threat to the species in the southeast coastal area of the mainland.
However, the crisis in the southeastern coastal areas of the mainland has not yet been resolved, and as people gradually discover that raising "big-headed fish" affects the juice of fish farming, or are harmed by big-headed fish, they will release them into other places such as the Yangtze River.
In fact, big-headed fish are alien species, like "alligator gar", and the act of releasing big-headed fish will not only affect the normal growth of farmed fish, but also pose a threat to native species.
The reason why bighead fish farmers have this attitude towards the way they are farmed is not because they are unaware of the dangers of releasing alien species, but because they want to absolve them of responsibility.
Release of alien species.
The release of alien species into the Yangtze River has caused harm in 2019, and at the end of 2019, there was a very high concentration of alien species release in many places in the Yangtze River basin.
It can be seen from the extremely large number of big-headed fish found in the Yangtze River basin that the harm is extremely great.
With the increasing number of alien species, some researchers are studying the big-headed fish, and through the study, the breeding cycle of the big-headed fish is very fast, as long as it takes six months to spawn.
And the amount of eggs each time is not low, about two catties of big-headed fish can lay about four catties of eggs, and the egg sac of big-headed fish is only about one centimeter, so that you can make full use of the space to store more eggs.
After hatching, the survival rate of raw fry is extremely high, and the egg sac of the big-headed fish is only one centimeter or even smaller than the egg sac of the native species, which is one centimeter in size, so that more eggs can be stacked.
After the observation and research of researchers, the number of alien species increases, and the advantage is greater than that of native species, leading to the extinction of native species.
Too many alien species will pose a great threat to the native fish of the Yangtze River, and alien species will also disrupt the food chain and ecological structure of the Yangtze River, resulting in an unstable state of development.
This will affect the normal reproduction of native species, because after all, alien species occupy a dominant position, which will limit the breeding space of native species, resulting in the normal reproduction of native species.
Therefore, the release of alien species will affect the ecology of the Yangtze River, damage the ecological environment of the Yangtze River, and even affect the number of native species, leading to the extinction of native species, which will have a great impact on the ecological environment of the Yangtze River.
epilogue
The release of alien species will have a great impact on the ecological environment of the Yangtze River, and even lead to great changes in the ecological environment of the Yangtze River, which is not conducive to the stable development of the ecological environment of the Yangtze River.
Of course, the fishing ban policy will inevitably cause new problems, so it is necessary to deal with and restore the ecosystem of the Yangtze River basin in a timely manner, just in case.