Species invasion has always been a difficult problem in this world, and many places are deeply disturbed by biological "invasion". For example, one day in 1900, hairy crabs were accidentally brought from China to Germany. In the following hundred years, hairy crabs were everywhere in Europe, and their number has grown to one million. You can see them in farmland and river beaches. The ecology of the city has caused a considerable impact, and the locals have no way of doing it.
my country’s crayfish is also an invasive alien species and is still included in the invasive list, but its damage to our country’s waters has been greatly reduced. Nowadays, it is necessary to rely on breeding to meet the needs of the public.
In addition, squid is flooding on American beaches, Danish oysters have also multiplied, and Australian hares are flooding in herds. These invaders who grow freely in other countries, are all delicacies in the eyes of Chinese foodies. Now, another invasive species is expanding all over the world, but this time China’s “foodie” is afraid that it will be too expensive. The reason is that it is too expensive. This creature is king crab .
In the Chinese market, a king crab costs hundreds of thousands of dollars at every turn. Many people feel that they can’t afford it. Because of its abundant protein content and rich nutrition, it can be called a "crab in the crab". "The King", deeply loved by consumers. However, such a large high-end food is an invasive species, and now it dominates Europe and Antarctica. What is going on?
01. King crabs are not "crabs"
King crabs are deep-sea crabs that are active in waters with a water depth of 850 meters and a sea temperature of 2-5°C. They can lie on the seabed in the cracks of rocks for a long time and are covered with thick shells. The carapace is relatively large and can reach 1.8 meters in length. The head and breastplate is about the same size as the palm of an adult. Its weight is about 5-10 kg, the largest weighs more than 20 kg, and its life span can reach 30 years.
However, there is actually a difference between king crabs and crabs in everyone's eyes. Crabs belong to the order Decapoda Brachyura, while the king crabs belong to the order Decapoda. It can also be distinguished from the morphological characteristics. Crabs generally walk sideways.They can also live on land, but king crabs can move forward and cannot live on land.
The king crab was originally produced in the North Pacific, Bering Strait and other waters. It mainly feeds on small fishes, shrimps and soft organisms on the seabed. Its nutrient content is quite high, such as vitamin a, vitamin E , protein, calcium, iron and zinc, etc., which can enhance the body's resistance, and it is very popular because of its delicious taste.
02. Why are king crabs flooding?
The proliferation of king crabs actually started from Russia. In 1961, the country’s ships docked in Norwegian ports, but seven king crabs were left accidentally. Prior to this, there was no king crab in Northern Europe, but because of the continuous reproduction of these seven crabs, by 1990 there were more than 50 million king crabs in the Norwegian waters, which was 10 times more than the population of the country.
It is reported that in the absence of natural enemies, a female crab can breed 10,000 small crabs a year, and the survival rate is 18%, so that is 2,000 crabs. The king crab is more adaptable, not only can grow in European waters, but can still reproduce rapidly even in Antarctic low temperature.
As early as 2011, scientists discovered more than one million king crabs on the Antarctic continent, which means that the Antarctic king crabs have also been flooded. Don't think this is a good thing. King crabs are difficult to carry out normal life activities at sea temperatures below 1.4°C. The proliferation of Antarctic king crabs indicates that Antarctic climate warming and sea temperature increase have allowed king crabs to thrive here.
As a kind of carnivorous food, the king crab does not have to worry about food in the vast ocean, and because of its large size, there are few natural enemies, so there is no obstacle to its reproduction. According to research, where the king crab goes, the number of creatures such as snails, starfish, jellyfish, sea cucumber , sea lily , etc. rapidly shrinks.Even on the verge of extinction.
Norwegian also thought about catching king crabs, but I never thought that the tongs of this creature are hard and powerful. The new fishing nets bought often need to be repaired after 1-2 times, which makes fishing more difficult. Fishing costs are also increasing.
Of course, king crabs also have natural enemies. The main natural enemies include wolffish and giant octopus. However, the number of these two kinds of natural enemies is not too much, and it is difficult to hinder the invasion of king crabs. At the same time, king crabs will stay in groups to keep warm. When encountering enemies, they will unite and cooperate with each other. The tongs are stacked into a three-meter-high crab wall to frighten off natural enemies. Because of this, the king crab has become a powerful predator in the sea, speeding up its expansion.
03. Why is it so expensive?
Some people are curious, since king crabs are everywhere in the ocean, why has it become a sky-high delicacy?
First of all, its catching cost is too high. After all, the sea temperature where the king crab grows is too cold and the size is too large, making it difficult to catch the crab. According to statistics, 1 in 7 crab catchers died. Therefore, the daily salary of crab catching is as high as $20,000, but even so, not many people are engaged in this industry.
The second is the restriction treaty signed by the Russian and Norwegian governments, which can only capture a limited amount each year. If you want to capture it, you need to get a license. In Norway, there are only more than 200 people with a catch permit, which limits their catch. The United States followed suit, stipulating that there is only a two-month capture period per year.
Because of this, the price of king crab has risen, and it has become a sky-high delicacy. However, it is the restricted capture and its high price that provide an opportunity for the spread and development of the king crab population. Nowadays, king crabs have seriously harmed the marine ecology, because they can adapt to the cold water temperature, scientists are worried,They will pose a great threat to the Antarctic ecology in the future. This matter is very worrying! It can be seen that every time everyone eats one, they are contributing to the ecology.
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