#头条创作挑战赛 #
For so many years, the ballet fairy in Cabin in the Woods has been the original horror character I find the most awkward movie, although it appears for a few seconds.
Sea lamprey
Sea lamprey is the bar handle of more than 40 species of lamprey eels, up to 1 meter long, they are the most primitive fish-shaped animals, living on Earth for more than 350 million years, surviving no less than four major extinction events. Their construction is also primitive enough, strange enough.
Sea lampreys are very similar to sharks, and although they look intimidating, they are both soft bones; The gill holes on the left and right sides are really bizarre; They will spawn in the upper reaches of freshwater like salmon and return to the sea when they grow up; Like frogs, they will undergo metamorphosis.
Then they drop their mouths, disc-shaped mouths filled with concentric round teeth made of keratin that can firmly hold themselves to their prey, and then stick out their beak-like tongues and stab into the flesh, gulping down blood.
Although it sounds like a thief, the existence of the sea lamprey is actually a blessing in the native land, and their juveniles can be used as food for a variety of aquatic animals; Living on riverbeds, the larvae act as decomposers, breaking down dead or decaying substances that other animals cannot eat, helping nutrients circulate through the food chain.
When the sea lamprey grows up to return to the ocean, many animals will wait at the mouth of the river for the influx of lampreys to ring the bell of the canteen.
After being eaten from childhood to adulthood, the number of sea lampreys that really enter the marine life is not much, and the sea lamprey eels are very rich and poor, they coexist peacefully with most fish, only looking for big fish to parasitize, these big fish can resist their hardcore relatives without easily go die.
But when they are forced to become invasive species, it's terrifying.
How the sea lamprey became the villain of the Great Lakes
In the 1880s, the sea lamprey was built because of the construction of the canal, and it entered the Great Lakes from its origin. There are few natural enemies here, and lampreys multiply in the Great Lakes at a rate of 100,000 eggs at a time. At the same time, the fishing industry in the area collapsed, the fish in the lake were not familiar with the sea lamprey, and they were naturally not as large as the sea, and the fish under 18 kilograms could not withstand the hardcore kissing of the sea lamprey, and were directly burped by a few mouthfuls. Fish attacked by marine lampreys have a mortality rate of 40 to 60 percent, and even if they survive, the injured fish spend more energy on healing than on spawning and mating, leading to a decline in fish populations.
In the 1940s, the United States and Canada fished about 6,803 tons of lake trout per year in the upper reaches of the Great Lakes. But by the 1960s, that number had fallen to 136 tonnes, second only to the previous 2 percent.
Lamprey control and management
That doesn't work! Money is involved! In 1954, the United States and Canada joined forces to form an organization called the Great Lakes Fisheries Commission (GLFC). The name of this organization is very grand, but it has only one purpose: to kill the sea lamprey.
Scientists screened more than 7,000 substances to develop two poisons that target only sea lamprey eels, which are mainly composed of 3-trifluoromethyl-4-nitrophenol (TFM), which is harmless to most fish and will be naturally degraded. Each year, wildlife officials dump about 79 tons of this venom into streams that flow into the Great Lakes, killing 98 percent of the marine lamprey larvae, and officials rely on small dams or barriers to prevent sea lampreys from migrating upstream to spawn.
At a cost of about $25 million a year, sea lampreys once destroy more than 45,359 tons of fish in the Great Lakes each year, but fewer than 4,535 tons are now dead as a result of them.
Scientists are now exploring more creative ways to suppress lampreys, including applying odors and pheromones to lure them into traps and sterilizing them.
The status quo and the indigenous people suffer
The control of sea lamprey is very effective, and the total number of sea lamprey eels in the Great Lakes is similar to that of 50-60 years ago, and has not increased, which is due to continuous control.
But with global warming and the pandemic, the two major human-bred twins seem to fluctuate, and scientists began modeling lamprey populations in lakes to understand how changes in temperature, weather, control measures, and other aspects affected lamprey population levels.
Then why not just kill them all and finish it?
Because the Great Lakes have other lampreys native to the Lake, these means are not clever enough to distinguish between different lampreys. Therefore, the development of a chemical control agent that is harmful to sea lamprey but not deadly to native species is one of the primary objectives of the Great Lakes Fisheries Commission, which can only be treated equally at present, after all, the impact on fishery production is really a bit exaggerated.