Asia’s Rare River Titans: These Giant Freshwater Fish Are Disappearing

Asia is a land of extremes. It is home to the world’s tallest mountain range (the Himalayas) and one of the world’s greatest forest stretches (Eastern Siberia’s enormous taiga). Furthermore, Asia is home to half of the world’s ten longest rivers, including the Yangtze, Yellow, and Amur Rivers.

These vast river systems are home to some of the world’s largest and oddest freshwater fishes, many of which have had catastrophic population declines in the last decade, making them nearly mythological.
Siberian taimen (Hucho taimen)
The Siberian taimen is a salmon family member endemic to northern Asia, with the majority of its present population living in Mongolia and Russia’s the Far East. Taimen resemble the more widely known salmon and steelhead trout, but they do not have an ocean-going phase of their life cycle, instead spending their whole existence in the region’s isolated rivers and lakes.

The Siberian taimen is the world’s biggest salmonid fish, and its size is startling. Some can grow to be six feet long and weigh more than a hundred pounds. While this does not make them the world’s largest freshwater fish, it does make them an intimidating addition to their vast, wind-swept drainages, where they terrify the local wildlife as apex predators.

Food is anything that can fit in a taimen’s mouth. Usually, this implies other fish — and even another taimen — although rodents and ducks are also fair prey. This predatory enthusiasm has earned them the moniker “river wolves,” and it has drawn fly fishers from all over the world looking for a massive, hungry target to catch and release.
Their reputation as river-bound terrors extends into area legend, which frequently depicts the creatures as possessing whale-like dimensions, superhuman power, and murderous impulses. Tales of mystery boat-sized fish in China’s Kanas Lake are still regarded to be exaggerations of a very genuine, maybe jumbo-sized taimen population.

Unfortunately, because of their sluggish development and delayed sexual maturation, Siberian taimen are more vulnerable to human activities and harvesting than other salmonids. The International Union for Conservation of Nature (IUCN) has classed the species as “vulnerable,” with most other taimen species in Eurasia being severely The reduction is assumed to be the result of overexploitation and habitat degradation caused by gold mining and river gravel extraction.

Kaluga (Huso dauricus)
The aquatic home of the Siberian taimen of Russia and China’s Amur River is shared with another enormous fish – one large enough to casually consume even the heaviest taimen as a snack. Meet the kaluga sturgeon, which can only be found in the Amur basin.

While most sturgeon are famous for their enormous size, kaluga are among the largest, only slightly outweighed by their close European relative, the 2,200-pound beluga (Huso huso.) The kaluga, on the other hand, has a more predatory nature, tearing at salmon, herring, pike, and just about any other fish that gets in its way. This is no small effort for the kaluga, which may grow to be about 19 feet long and weigh more than a ton. This would imply that it is the largest of all freshwater fish, but the species, like the beluga and many other sturgeon, does not spend its whole existence in freshwater, developing at sea and returning to rivers to breed.

Kaluga is now on the verge of extinction, has been widely (and frequently illegally) harvested for their roe (eggs), which are prized as caviar.
Chinese Paddlefish (Psephurus gladius)
Paddlefish are sturgeon cousins with a paddle-shaped snout lined with electroreceptors that help them identify food in murky situations.

Only two species have survived to the present day: the American paddlefish, which is native to the Mississippi River Basin, and the Chinese paddlefish, which is only found in the Yangtze River Basin. Chinese paddlefish differ from their American counterparts in that their “paddle” is proportionately longer and more blade-shaped, resembling a strange deep-sea creature (such as the goblin shark) rather than a river fish.

It’s also bigger than the American version. Significantly bigger. Unsubstantiated reports claim that Chinese paddlefish may grow to be 23 feet long and weigh thousands of pounds. According to more trustworthy accounts, the greatest estimated size is ten to twelve feet tall and several hundred pounds.
Unfortunately, little is known about their biology other than their general migratory tendencies; the fish spend the winter in the Yangtze and it’s saline estuary before migrating upwards to breed in the spring.

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