In any ecosystem in the world, many endangered species, including freshwater ecosystems, continues to decrease in population. 

Freshwater biomes are water sites that have low amounts of salt. These ecosystem types include streams, rivers, lakes, ponds, and wetlands. 

In many freshwater biomes around the world, mammals, reptiles, and fish species are in danger of becoming endangered. 

The global extinction in freshwater habitats, including fish, rodents, amphibians, and mammals, have been quantified for the first time by researchers, and the findings paint a dire future. The global populations of these freshwater animals have decreased by almost 90 percent over four decades since 1970, twice as much as the decline of vertebrate populations on land or in the oceans.

Here are four freshwater Species that are continuously dwindling in numbers:

Hippopotamus

The name Hippopotamus in Greek means "river horse." 

The large creatures are present in rivers and lakes in Africa. The large creatures are present in rivers and lakes in Africa. To keep its body cool, it spends up to 16 hours a day in freshwater. It either walks on the bed of the river or lies in shallow waters. 

In the night, hippos travel up to six miles on land in a single file to graze. 

Hippos were placed in 2006 on the list of endangered species. The biggest threat to the species is that the ivory in its teeth is killed by poachers.

Hippos are currently restricted mainly in protected areas, and their numbers have decreased 7-20 percent over the past 10 years. 

The two hippos, the common hippo and the pygmy hippo are respectively classified as vulnerable and endangered.

Related Article: Next Extinction Target: World's Freshwater Fishes

American Crocodile

A species of reptile found in western Mexico, Ecuador, and southern Florida is the American crocodile. It has a long tail that glides across the water and a muscular body. To encourage it to walk on the ground, it also has webbed feet. Fish, insects, snakes, and birds are nourished by the American crocodile.

To capture its prey, it uses its powerful jaw and rows of sharp teeth. It drags the prey underwater until captured and wrestles until the prey is gone. It has been hunted by humans for its skin in the past and is now under threat due to the destruction of its wetland habitat.

Manatee

In Africa and South America, manatees are mammals that dwell in rivers. In pairs or small groups, a manatee stays. Like all marine mammals, it must breathe on the surface of the water, but otherwise it will still live-in water.

To help it fly at an average of 5 miles an hour, it has a powerful tail. It was born underwater and can swim unassisted within an hour. It consumes weeds, algae, and water and lives in the wild for up to 40 years. Owing to habitat destruction, manatees are vulnerable and are at risk of being struck by motorboat propellers.

Sturgeon Fish

They are native to subtropical, temperate, and sub-Arctic seas, lakes, and coastlines of Eurasia and North America and are among the oldest bony fish families in existence. The bulk of sturgeons are anadromous bottom-feeders in river deltas and estuaries, breeding upstream and feeding. Although some are fully inland, so few go outside coastal areas into the open ocean.

Some species of sturgeon, which is turned into caviar, are harvested for their roe. They are more vulnerable to overfishing because of the late sexual maturity of sturgeon (6-25 years).

The number of sturgeons in large basins is estimated to have fallen over the last century by 70 percent. The overall catch was significantly increased by unprecedented illicit logging during the 1990s. Poaching activity is estimated to be 10-12 times above the legal limits in the Volga-Caspian basin alone. 

Water contamination, damming, degradation, and disruption of natural watercourses and ecosystems that threaten migration routes and feeding and breeding grounds are causing more problems.

ALSO READ: Animals That Went Extinct In 2020 (and some that might disappear in 2021) 

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