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< h1 class="pgc-h-arrow-right" > introduction</h1>
The biodiversity of the Lancang-Mekong River Basin is second only to that of the Amazon River Basin, and the variety of animals and plants is very rich, known as the "Natural Museum of Animals and Plants". There are more than 1,700 species of fish, and four of the top ten freshwater super fish in the world are listed in the Mekong.
The Mekong River is the "fish barn" of Southeast Asia. What are the large freshwater fish in the Mekong Basin? What does the Mekong River rely on to feed so many fish? Like the Amazon, the Mekong River is able to feed so many fish by a unique ecosystem because it has a "retractable stomach" – Tonle Sap Lake, which plays a vital regulatory role.
Outline of this article:
The Mekong River has large freshwater fish and abundant fish resources
The reasons and determinants of the mekong's abundant fish resources
The effective functioning of the Mekong's unique ecosystem is a guarantee of fish reproduction
The importance of fish resources in the Mekong
<h1 class= "pgc-h-arrow-right" >, what are the large freshwater fish and abundant fish resources in the Mekong River</h1>
The Lancang-Mekong river system runs in a north-south direction, with high north and low south, with a huge difference in altitude, and the distribution of fish has transitioned from cold-water fish in the north to warm-water fish in the south. Because of the climatic zone, there are few species of cold-water fish and fewer large fish species; there are more warm water fish species and more large fish species.
The upper reaches of the Mekong River above Vientiane to China's border areas, the middle reaches from Vientiane to Pakse, and the lower reaches from Pakse to Ho Chi Minh City. The downstream channel widens and the water flow slows down, which is a rich area of water area and nutrients in the Mekong River, and there are the most large fish living in the mekong River, specifically the following giant fish species.
Mekong River Basin
Giant bass
It is distributed in three regions: the Ganges River in India, the lower reaches of the Lancang River in China, the Yuan River, and the Mekong River in Southeast Asia. It is a killer of the horror level at the bottom of the river, in fact, it is a fish of the bass family, other fish of the family are some small fish and shrimp level, but the giant is the giant of this family, is the face value of the entire family, and it is mighty and huge. It dominates the middle and lower reaches of the Mekong River, but it has a weakness, spawning requires a suitable water temperature, and long-distance migration to the lower reaches of the Lancang River in China to lay eggs is easy to be captured.
The ethnic minorities in southwest China call it "noodle melon fish", and the color of the fish is orange, like pumpkin, so there is the elegant name of the melon fish. But it is not vegetarian, very fierce, low in stature, wide mouth and fangs, and even a little vicious and terrifying. Animals and even humans crossing the river will be ambushed by it, and it likes to stay in deep waters. Because of its fierceness and domineering, there is no shortage of fish lovers in China who like to raise it, and its sharp eyes have made it get the title of "eagle duck's mouth".
Giant Siamese (xian) Roach
Siam is the name of ancient Thailand, so this large carp is called the giant Siamese carp, revered as the national fish of Thailand. Also enjoying the title of "national fish" is the koi of the island country. The giant Siamese carp is the largest species of carp in the cyprinid family, growing to more than 3 meters and weighing more than 600 catties. But the giant Siamese carp is a vegetarian, does not attack other fish, and can form a "peace and friendship group" with elephants on land and manatees in the sea. The domestic aquarium community likes to raise its juveniles as ornamental fish.
Giant Siamese carp
Giant stingray (freshwater red stingray)
Chinese scientific name is the scaly sand stingray (hong), and the giant freshwater stingray is one of the largest freshwater fish in the world. It is widely distributed in marine and freshwater rivers, such as the Amazon River, Australian Rivers, etc., and the Mekong River is distributed in Cambodia, with the largest individual reaching 5 meters and weighing 180 pounds. It likes to bury itself in sand or silt at the bottom of a river, breathing through a hole in the top of its body or a spray hole. Be very careful when catching stingrays. Stingrays have a root spine in their tail that pierces through a person's skin and bones and injects venom into the human body.
Mekong giant stingray
Toothless [Fish Mang] (Mekong Catfish)
It is a species of fish in the family Megalobiteae, the genus Odonta. Also known as the Mekong River Catfish or Mekong Giant Catfish, it is a giant catfish endemic to the Mekong River in Southeast Asia. This catfish has teeth in its larval stage, and when it becomes adult, it magically becomes toothless and beardless. It doesn't need teeth and needs to find food, its food is different, it turns out to be a herbivorous fish, which is unique among catfish. Adults average about 3 meters long and weigh more than 300 pounds.
Mekong giant catfish
Doman fish: Distributed in the Mekong river system, the Malay Peninsula, Sumatra and Kalimantan. It is the second largest species of fish in the family Ichthyosaurs, and is the same species of fish as The Blackfish in China, but it is not at all in the order of magnitude.
Broodstock are very fierce during the breeding season, have juvenile behavior, and will attack humans who approach it. Feeds on fish and shrimp, aquatic insects, frogs and birds. Body color can vary with the environment, usually greenish-brown or olive-green, with a dark longitudinal band on the side of the adult body, a white belly, and juveniles suitable for ornamental fish culture.
In addition to the above large freshwater fish, there are many other fish species in the Mekong River. There are more than 1,700 species of freshwater fish, second only to the Amazon Basin in abundance. Such as largefin fish, seven-star knifefish, Thai bamboo shoot shell fish, various catfish, forktail catfish, Genghis Khan shark (filament [fish]) and so on. We can learn a thing or two from the fish markets in Southeast Asian countries.
Silktail turtle (hu): It is also distributed in the Lancang River in China, weighing about 40 catties. Its dorsal fin is semicircular obliquely fan-shaped and very different from the dorsal fin of the Genghis Khan shark.
Silk-tailed bird
Big Fin Fish: The Big Fin Aquarium is called Moonlight Burst Tooth, and the Amazon River's Tooth Breaker is not a level fish species. It is a fish of the order Cyprinidae, Cyprinididae, subfamily Cyprinidae. It can grow to about 50 cm and is distributed in the freshwater basins of the Mekong River Basin in Asia, Indonesia, Vietnam, Thailand and other places, and is an economical edible fish, and can also be raised as an ornamental fish. Prefers to live in the upper layers of water bodies, carnivorous.
Thai bamboo shoot shell fish: it is farmed in the two Guangzhou areas of China and often appears on the table of China's coastal cities.
Seven-star knifefish: The scientific name is the ornamental armor bowfish, which can be raised as an ornamental fish, also known as the seven-star flying knife. It has bony teeth on the tongue and belongs to a large family like the Arowana and the Arapaima. Distributed on the bottom of the Mekong River Basin in Asia, it feeds on fish, crustaceans, etc., and prefers to move in the early morning and dusk. The small one is the Siamese single-kissed fish, which is the raw material for the Cambodian people to make fish sauce.
Forktail catfish: Like the catfish in Guangxi, China, it has a skirt-like ventral fin and swims very beautifully.
Forktail catfish
<h1 class= "pgc-h-arrow-right" > second, the reasons and determinants of the abundance of fish resources in the Mekong River</h1>
The links that affect the survival and reproduction of fish mainly include three aspects: water resources - food sources - temperature.
The Mekong river system is rich in fish resources and has key natural causes, which can be summarized as follows: tropical climate, abundant water volume, and abundant food sources.
1. Abundant water resources
Whether a river system can raise more fish, the most important link is that the water resources should be abundant, and the water cycle in this area is like this:
During the rainy season, the warm and wet monsoons of the Indian Ocean carry a large amount of water vapor, blowing from southwest to northeast, and when they encounter snowy plateaus, they are lifted, forming the confluence of cold and warm currents to produce snowfall. When the monsoon is turning to the right, it encounters the Hengduan Mountains, which are composed of a series of north-south strips of continuous mountains, which have a similar speed bump and pipe effect on the road to the airflow, allowing the warm and humid air flow to wander along the mountain. Therefore, a vertical climate zone is formed in the three parallel rivers of Yunnan in China, which brings a large amount of water resources to the Mekong River in the upper reaches.
At the same time, there is a continuous mountain range from the Gaoligong Mountains in western Yunnan to Laos, and the cold and warm currents form a flat prototype tropical rainforest in Cambodia. The entire water system has a large amount of alpine snow melting and abundant water resources formed by rainfall during the rainy season, and the amount of water in The Khong Waterfall in southern Laos is extremely large during the rainy season, and the waterfall channel can reach 14 km wide. It is 2 times the runoff of Niagara Falls.
Schematic diagram of the climatic environment of the Lancang-Mekong river system
2. Abundant food
With water resources, there must also be a special geological environment to bring rich organic matter, promote the growth of plankton, plants, etc., and bring abundant food to fish.
The area through which the Lancang-Mekong River basin flows has almost all the geological environment except for deserts, including snow-capped glaciers, meadow slopes, mountains, hills, plains, etc. At the bend of the Lancang River in Shangri-La, the river is mixed with a large number of sediment minerals, organic matter and insects flowing down the river.
The Lancang River makes a big turn
3. Suitable temperature
The world's biodiversity-rich areas, including fish, tend to be in the tropics, such as the world's three major tropical rainforests: the Amazon, Congo and Mekong rivers. These areas, located in the tropics and rich in water resources, naturally have many species. In contrast, Australia, although in the tropics, has limited precipitation and poor species diversity. Because of the cold climate in the northern hemisphere, the rivers in these areas are not as abundant as those in the tropical rivers.
<h1 class = "pgc-h-arrow-right" > Third, the effective operation of the mekong's unique ecosystem is the guarantee of fish reproduction</h1>
Improving the interdependent ecological regulation system can leave water resources and nutrients behind, convert nutrients into fish bait, and provide fish with living space and abundant food sources, all of which are inseparable from the unique ecosystem of the Mekong River. How does the Mekong ecosystem work?
If the Lancang-Mekong river system is likened to a robust person, then the Qinghai-Tibet Plateau is his brain and central nervous system; The Orange Well to Kong Eun Waterfall is his spine; the Tonle Sap Lake is his stomach; the Mekong Delta and the floodplain are his good intestines for digesting and absorbing nutrients.
Schematic diagram of the Mekong ecosystem cycle
1. Tonle Sap Lake plays a role in regulating the regulation of water resources during the abundant and dry periods, and is the "telescopic stomach" of the Mekong River.
The reason why the Amazon Basin is so rich in fish is to grasp the two key points of water and nutrients, and the Mekong River has done the same, but the specific mechanism of realization is different. The Amazon River uses the rainy season to let the waters of the river wander around the vast Amazon plains like wild horses that are out of rein. The Mekong River adopts the expansion function of the Tonle Sap Lake and can feed the river during the dry season.
Tonle Sap Lake is a swallow-type lake, also known as Phnom Penh Lake, it also has a nickname called "Fish Lake", which is the largest freshwater lake in the world with the largest fish production. When the rainy season comes, floods wash fish, eggs and juveniles scattered in tributaries of the rivers into Lake Tonle Sap, which is a temporary refuge and breeding ground for fish during the flood season. The abundance of sediment brings an abundance of organic matter, providing a large food source for fish to survive in Theungle Sap Lake. During the rainy season, Tonle Sap Lake is more than six times larger than the dry season lake area, and the abundant food attracts many fish from the ocean to spawn here.
Comparison of the area of Tonle Sap Lake during the rainy and dry seasons
Tonle Sap Lake is home to the ancient Angkor culture and is the most important fish and rice producing area in Cambodia. Since ancient times, according to the characteristics of the "stretching stomach" of Tonle Sap Lake, the Cambodian people have enclosed the shoals with tree stumps during the dry season, and when the rainy season comes, the juvenile fish come from the river to the Tonle Sap Lake and enter the wooden stake area to live. When the water recedes during the dry season, delicious fatty fish are harvested in the stakes.
Stone carvings of fish and labor scenes in Angkor Wat, Cambodia
Unlike other lakes, Tonle Sap Lake produces both downstream and countercurrents, with rivers rising above the lake during the rainy season, and rivers flowing into Tonle Sap Lake, creating floodplains. During the dry season, the lake level is higher than that of the river, and the water of the Tonle Sap Lake flows into the Mekong River through the Tonle Sap River to replenish the river. Fish migrate out of lakes and into rivers to spawn.
The process of downstream and countercurrent occurrence of Tonle Sap Lake
Tonle Sap Lake during the rainy season
2. The floodplain of the Mekong Delta at the mouth of the river is rich in water and food, which is the "intestine" of the Mekong River.
Cambodia's lakeside plain is 500 kilometers long and more than 110 kilometers wide, with fertile land, longitudinal rivers and swamps, and the Mekong Delta together form the "Central Great Plain" of the Mekong River. During the rainy season, the intricate waterways act like intestines, transforming the alluvial materials, countless insects and microorganisms, and weeds brought by the Mekong River into natural feed for nourishing fish.
When the dry season comes, the fertile silt fields of these floodplains become fertile fields again, producing high-quality rice. At this time, fish living in the Mekong Delta go down the river into the Kon Waterfall section of the Orange Well Road to spawn.
During the rainy season, floodplains of the Mekong Delta
The water network of the Mekong Delta
3. The deep pool from Kong'en Waterfall to the Orange Well River provides shelter for fish in the dry period, and is a "refuge and delivery room" for fish in the Mekong River.
In Pakse, on the border between Laos and Cambodia, there is a large waterfall with a small gap, but the flow is amazing, known as Khong Falls or Khong Nhong Falls, which is nearly twice as high per second as Niagara Falls. It becomes a huge obstacle to navigation upstream and downstream, but it is a blessing for fish.
During the rainy season, it becomes a 14-kilometer-wide waterfall area, and beneath the waterfall are many large deep pools with a depth of 30 meters, and this low-lying section of the river is very similar to the vertebrae of human beings, which is the "spine area" of the Mekong River. This area is also a very unique part of the Mekong River, a refuge for large fish during the dry season (November to April) and a "delivery room" for other fish.
There are many deep pools in this section of the river, allowing many large fish to inhabit it during the dry season. For other fish, this is an spawning and breeding area, where the eggs hatch and are washed into the bait-rich Tonle Sap Lake as the rainy season approaches.
Khong N waterfall in southern Laos is a fish spawning ground and migration channel
summary:
Rainy season (May to October): The river level rises sharply, flowing into the Tonle Sap Lake and mekong Delta region, the lake area is expanded 6 times, forming a large flood area, fish larvae enter the Tonle Sap Lake with the water flow, and a large amount of sediment organic matter from the water also enters the lake area, providing food for fish growth. At the same time, it attracts many marine fish to swim here to ask for bait.
Dry season (November to April): The waters of Tonle Sap Lake flow into the Mekong River, and fish follow the current from Tonle Sap Lake into the Mekong River and migrate to the middle "spine area" to spawn. Large fish living in the Mekong Delta region also migrate to the deep pools of the "spine area" to survive, and then cross the waterfall area during the flood season to spawn and migrate to the Huoyuan River (Luosuo River) in the lower reaches of the Lancang River in China.
Giant bass and silk-tailed turtles migrate long distances | Other fish migrate short distances
<h1 class= "pgc-h-arrow-right" > the importance of fish resources in the Mekong</h1>
Due to the intensification of human activities, the fish resources of the Mekong River are decreasing, and the construction of dams on the rivers has cut off the migration routes of fish, changed the water temperature requirements when fish breed, and hindered the delivery of nutrients in the water body throughout the water system. It poses a problem for the survival and reproduction of fish. In particular, one-eighth of the daily protein needs of the Cambodian people depend on the fish of Tonle Sap Lake. Rice and fish are two of the main food sources for the Cambodian people.
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