Japan is a famous fishing country. Although its land area is only 377,000 square kilometers, it is extremely rich in marine resources. The island nation is surrounded by sea and has a marine exclusive economic zone of about 4 million square kilometers, which is more than 10 times the land area.
Japan not only has a vast sea area, but also has world-famous super fishing grounds. At the intersection of the Japan Warm Current and the Chishima Cold Current, the Hokkaido fishery came into being, rich in commercial fish such as salmon, pollock, and saury. With this blessing, Japan achieved a catch of 12.816 million tons in 1984, ranking first in the world.
The fishery species caught in Japan involve more than 100 aquatic animals and plants, and show a trend of moving from shallow sea to deep sea. In the process of exploring the deep sea, new fish species are constantly being discovered and named. Are there new opportunities behind this?
Rare new fish species discovered in Japanese waters
According to news from the Japan Broadcasting Association on July 1, scientific researchers discovered a huge strange fish in the deep sea of Suruga Bay, Shizuoka Prefecture, Japan, and later named it Yokozuna Sardines (Narcetes shonanmaruae), Japanese name is Yokozuna iwashi.
As you can see from the video, this giant creature is black all over and looks like a catfish. It has a thick head, a large mouth and an estimated body length of 2.53 meters. It is a veritable deep-sea giant.
Since 2016, the Japanese scientific research team has caught four fish of the same species in the deep sea between 2100 and 2600 meters, with body lengths ranging from 1.2 to 1.38m. The size of the large fish discovered this time set a new record, and the location was different from the previous one off Hachijo Island. This also shows that Yokozuna sardines are likely to be widely found in the deep sea of the North Pacific .
Scientists analyzed the stomach contents of yokozuna sardines and found that is a carnivorous fish that is at the top of the deep-sea food chain. A professor at Tokyo Marine University in Japan also said that the big fish captured opened its mouth wide and tried to intimidate the surrounding deep-sea fish. "This behavior is a typical behavior of carnivorous fish that stick to their territory and drive away other creatures."
Netizens lamented this: The deep sea is mysterious and unpredictable, and there are probably more "giant things" behind it that have not been discovered! Indeed, the appearance of big fish hints at the existence of unknown ecosystems in the deep sea, because only a sound food chain and sufficient bottom biological resources can support large predatory fish.
Deep Sea: A little-known magical secret
The ocean occupies 71% of the earth's surface, but so far, human exploration of the ocean has only reached 5%, and the other 95% is still full of mystery and unknown. This is especially true in the deep sea, where humans currently have only a small window of observation.
What is the deep sea? According to international definitions, the sea area below 200 meters belongs to the deep sea.
In the range of 0~200m, seawater has good light transmittance and rich primary productivity. This is the area where life phenomena in the ocean are most prosperous. When the water depth reaches below 200 meters, the sunlight is already very weak, the biomass of producers drops sharply, and biological resources such as fish are greatly reduced.
When the water depth is below 1000m, you enter the deep sea layer. You cannot see any sunlight, the water temperature is close to freezing point, and the pressure exerted on the surface of living things exceeds 100 standard atmospheres. What is this concept? On an area of 2 square centimeters of , the pressure withstands exceeds 100 kilograms! High pressure, low temperature, and lack of food have brought almost harsh conditions for the survival of deep-sea creatures.
Therefore, some people believe that the deep sea is a restricted area for life, and it is difficult for large fish to survive in it. But is this really the case? Is there no grass growing in the deep sea, or is there a hidden world?
With the continuous improvement of deep diving capabilities, people gradually realize that there is indeed a spectacular world of life in the deep sea! Scientists have discovered through research that organic life forms are common in the deep sea. The number of potential life groups is estimated to be more than 10 million. The metabolic mechanism is unique and has great scientific research value.
Among them, many giant deep-sea creatures are impressive.For example: king physalis (up to 11 meters), deep sea stingray (up to 2.7 meters), deep sea oarfish (up to 7 meters), giant spider crab (leg width up to 3.7 meters), deep jellyfish (up to 10 meters) and other species. These are creatures that actually exist in the deep sea, and they are quite large, which means that the deep sea has a considerable source of nutrients.
In April 2022, 40 scientific researchers from 17 countries including the United Kingdom formed a deep-sea scientific expedition team and took more than 11,000 photos and videos deep in the Atacama Trench along the coasts of Peru and Chile There are more than 100 hours of data, and a large number of deep-sea species have been discovered, including three newly discovered lionfish.
In short, the deep sea is not as dead and silent as people imagine, but full of unknowns, and more mysteries need to be further explored.
The "protein library" of the deep sea: What is the food source?
If a species wants to survive, it must be supported by food. In the deep sea, there are two main sources of food.
First of all, there is primary productivity in hydrothermal areas in the deep sea.
The seabed is rich in geothermal energy . Volcanic movements have formed unique hydrothermal areas, forming a typical extreme environment on the earth. In these high-temperature waters, hydrogen sulfide and minerals are abundant, supporting the growth and reproduction of seabed bacteria.
These bacteria are chemoautotrophs and do not require light to survive and play the role of producers in the food chain. Protists at higher trophic levels feed on bacteria, and organisms such as shrimps, crabs, and shellfish also take a share of the pie, forming a magical deep-sea food web.
Take the giant tube worm as an example. This tube worm lives in hot spring waters between 2 and 30 degrees Celsius. It can tolerate extremely high concentrations of hydrogen sulfide and can reach a body length of 3 meters. Deep-sea tubeworms live in symbiosis with chemoautotrophic bacteria and skillfully convert inorganic carbon into organic carbon to complete their life history.
Secondly, " whale falls " opens up the nutrient channel between the upper and lower layers of the ocean.
"Whale fall" means that after the death of whale creatures, the corpse gradually sinks, eventually forming a unique ecosystem on the seabed. The phenomenon of whale falls is like an oasis in the desert, providing important food supplies for deep-sea creatures. In the deep sea of the North Pacific alone, whale falls support the survival of at least 43 species and a total of 12,490 organisms.
Deep sea whale falls
Where whale falls are found around the world
What is the significance of the existence of whale falls? It speeds up the transfer of marine organic matter from the upper layer to the middle and lower layers, thus acting as an "ocean carbon pump".
According to scientists' estimates, a 40-ton whale can provide 2 tons of carbon to the deep sea after death, which is equivalent to the total amount of carbon accumulated in one hectare of seabed in 100 to 200 years. Wherever whale falls occur, there are usually 3 to 5 trophic levels of organisms gathered, with a wide variety of species and extremely prosperous life phenomena.
In 2020, Chinese scientists discovered a 3-meter-long whale drop in the South China Sea. Dozens of white armored shrimps, red shrimps, and multiple weasel fishes gathered nearby. The tail of the whale can be seen with the naked eye. Several deep-sea fish were observed feeding. From a practical point of view, whale fall is a carnival feast for deep-sea creatures, and it is also the last "feedback" of whales to the ocean.
How valuable are deep-sea fish?
The deep sea is an attractive deposit of biological resources. According to the results of the " International Marine Life Census Program ", there are more than 17,000 known species living in the deep sea area of 200~5000m, with huge development potential.
How rich are the biological resources of the deep sea?
According to the survey and evaluation of the Japanese fishery research team, the catch of fish and other organisms is expected to reach about 30 million tons in water depths of 200 to 2,000 meters alone, which is equivalent to 1/4 of the world's total fishery production.
From the perspective of feasibility, the operating depth of deep-sea fisheries has reached 3,000 meters, and deep-sea fish have the potential for commercial development.The toothfish in Antarctic waters is a typical example. This fish is also known as Antarctic cod. Its meat is tender and white, and it is recognized as the "noble fish". In 2010, the price of 1 ton reached 10,000 US dollars, which is as valuable as tuna .
Tooth Antarctic fish/Antarctic cod
According to statistics, there are currently 7 to 8 families of deep-sea fish that are targeted for fishing, and the resource reserves are quite attractive.
Among deep-sea fish, lanternfish account for an important proportion, as high as 65%. According to Wikipedia records, lantern fish is the most widely distributed and abundant deep-sea fish in the world, with global resource reserves of about 5.5 million tons to 660 million tons.
In addition to fish, the krill resources in the deep sea are also considerable. As early as 2008, British scientists discovered Antarctic krill in the deep sea of 3,000 meters in Antarctica, and the reserves were also astonishingly large. "Current Biology" (Current Biology) journal pointed out that the biomass of Antarctic krill is as high as 500 million tons, which is almost an inexhaustible "protein resource library" .
In 2020, the global catch of Antarctic krill is only 450,000 tons
On the other hand, the development of deep-sea organisms also needs to be cautious. Many deep-sea fish grow slowly and have a long life expectancy. After being overfished, it is difficult to expand again, so they can only maintain a very low development rate. In order to protect deep-sea organisms, resource management must be strictly formulated, scientifically evaluated, and reasonably maintained.
