Amazon Freshwater Stingrays Gain Much-Needed Protection — Will It Be Enough?
Amazon Freshwater Stingrays Gain Much-Needed Protection — Will It Be Enough?
Published via The Revelator
Two little-known and rarely studied species of freshwater stingrays — yes, such a thing exists — just gained enhanced international protections, but will it be enough to save them?
That’s the debate echoing out of the latest meeting of the Convention on the International Trade of Endangered Species, which in November voted to protect two colorful species of Amazon stingrays: the Xingu River ray (Potamotrygon leopoldi) and the Rio Negro Hystrix ray (P. wallacei).
The move represents a rare victory for freshwater stingrays, who are relatives of sharks, says Patricia Charvet from the Federal University of Ceará’s program on biodiversity conservation. She has spent decades advocating to protect these species.
“It’s a big challenge,” she says. “People only think about the sharks and rays that live in marine ecosystems, while freshwater species get ignored.”
While some, like Charvet, consider this a big victory, other experts expressed concerns that the situation for freshwater stingrays in the Amazon is more complicated and that these new CITES listings leave other related species unprotected from the same threats.
Unstudied Species
Amazon stingrays live in most of South America’s river basins, not just the Amazon, and are the only group of sharks or rays adapted to live their entire lives in freshwater.
This sets them apart from species such as bull sharks, which can enter freshwater but spend most of their lives at sea.
“They’ve lost the ability to accumulate urea in their blood, which is the main strategy used by sharks and rays to keep their body fluids in equilibrium with seawater,” says Luis Lucifora of Argentina’s Instituto Nacional de Limnologia.
In other words, it’s not that they don’t enter the ocean. It’s that they can’t.
Another thing that sets them apart is: They’re less well-known and less protected than their marine cousins.
But here’s what we do know: About 40 currently recognized species of these freshwater stingrays in four genera, although Charvet says some new species are being described. The Rio Negro Hystrix ray, for example, did not receive scientific descriptions until 2016.