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

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.

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