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Which chondrichthyans can live in freshwater habitats?
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chondrichthyan
Southern stingrays (Dasyatis americana or Hypanus americanus) are found in the western Atlantic Ocean.
While most chondrichthyans (cartilaginous fishes) are marine, several species are capable of entering or permanently residing in freshwater habitats.12
- Bull Sharks: The bull shark (Carcharhinus leucas) is one of the few shark species capable of living and breeding in freshwater environments. They have been documented far up major river systems, including the Amazon and Zambezi, and in lakes such as Lake Nicaragua.342
- Freshwater Stingrays: The family Potamotrygonidae consists of stingrays that are permanent residents of freshwater rivers and streams in tropical South America. Unlike marine elasmobranchs, these species appear to lack the urea retention habitus typically used to maintain osmotic balance in saltwater.56
- Other Species: Many other sharks and rays are known to enter estuaries and travel significant distances up rivers. For example, the sawfish is capable of moving into freshwater, where it adjusts its physiology by significantly increasing its urine output to manage water balance.16