"Fish Tour Class" on the Berlin River

[Global Times special reporter Wang Juan in Germany] Most people are no stranger to the seasonal "migration" of birds and mammals, but they know very little about the migration of fish. Some fish leave the original habitat during its life cycle and regularly migrate on a regular basis. This phenomenon is called "travel". In order to science fish living environment and habits related knowledge, and to improve people's awareness of the aquatic biological diversity and the river ecosystem, the "World Fish Traveling Day" came into being. This international initiative is held every two years, and the date is not fixed. The "World Fish Travel Day" in 2022 is scheduled to be on May 21. On this day, more than 1,500 public welfare organizations, schools, aquariums, zoos, communities and other institutions around the world have carried out activities in various places. Special reporters of the Global Times made a special trip to Berlin's two important rivers to learn about government departments, environmental protection organizations, and citizens to protect wild fish to protect wild travel.

The first stop is the Panciehe. This river originated from the junction of the northeast of Berlin and Brandonburg, and passed through the total length of 27 kilometers through the urban area of ​​Berlin. The reporter saw the researchers at the Leibnitz Institute by the river. They set up a small temporary science popularization exhibition about fish travel knowledge, and set up a simple aquarium containing the main fish species in the waters of Berlin. Researchers told the audience who came to participate in the special activities of the fish traveling day. Traveling was the result of the common role of fish, genetic factors, and external environment in the long process of evolution of fish. However, with the development of industrial and social progress, many ships, dams and hydropower stations have been built around the world. These artificial water conservancy projects often hinder the natural channels of fish travel. This situation is like when you encounter an unable to cross the road barrier on the way to drive, you need to set a road mark to guide the forward vehicles to turn and continue to move forward. The "Fish Road" is a remedy measured on the impact of human activities on fish travel. It has been recorded as early as the 17th century French literature -people use tied branches to make fish on steep river channels Taoism helps fish across the obstacles that cannot be passed by themselves.

The most common and easy form of various fish road forms is the "fish ladder". Researchers asked the audience to look at the center of the river, and the reporter noticed that there was a slow and low staircase hidden in the turbulent river channel. Even residents living nearby rarely noticed, or they would not think of such one Eye -eye installations are actually very good. Fish can use the fish ladder to go up against the current, crossing the barrier formed by the gap between the dam and the sluice without exhaustion. The fish ladder also has a lot of attention when designing. If you need to consider the slope and length of the fish species in the river to achieve the effect of controlling water flow, kinetic energy, and speed, it creates an environment suitable for specific fish tours.

Through the exhibition, the reporter also learned that there are many ways to scientifically classify fish travel. According to the reasons and purposes of the tourism, it can be divided into reproductive tours, warmth, and bait. According to the ecological environment where the fish is located, it can be divided into a trace of rivers (such as salmon from the ocean flow to freshwater spawning), the river descending (such as eel from freshwater flowing to the ocean breeding) The ocean -time tourism and freshwater tours correspond to the living in different stages in the ocean or freshwater areas in the lifetime, living in different ocean areas, and only living in different ocean areas, and only live in different freshwater areas. The common bass and barracuda in Berlin belong to fish with freshwater travelers.

The reporter then went to the History Port of the Siprean River in the Mi -Special Economic Zone in Berlin. In this waters, there was a ship lock built from 1936 to 1940. In recent years, the Berlin Water Road Construction Administration has re -planned the port function, demolished the old ship gate, and once again selected a new ship gate at 200 meters, which specifically planned a fish ladder. Interestingly, this fish ladder is not only suitable for tadpoles such as eel, sea bass and other fish, but also helps to migrate other small animals such as otters and beaver that also live in the river.

In recent years, not only in Germany and European countries, the awareness and emphasis on fishing for fish are deepening. According to the EU regulations, fish travel devices need to be added in existing or new water conservancy facilities. During the "World Fish Tour Day" every year, we can carry out rich and diverse activities in Europe, such as demolition of old dams and new fish roads, knowledge lectures and seminars, documentary screening, publishing and distribution books, organizations, organizations, organizations, organizations, organizations, organizations Citizens clean up the miscellaneous objects in the river and encourage families to assist scientific research institutions to collect fish and river monitoring data. In 2020, they also held a "European Fisheries International Singing Competition".

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