Florida's Freshwater Stingrays

What??? I had never heard of Florida having freshwater stingrays. When I think of freshwater stingrays I only think of the Amazon. Well, not anymore:

The most common reaction I receive from people when I mention that I conduct research on freshwater stingrays in Florida is “I didn’t know there were freshwater stingrays in Florida.” I’ve found this response to be so predictable and so consistent, ranging from people with Ph.D.s to G.E.D.s, that sometimes I question it myself. However, the truth is that stingrays are quite abundant in Florida’s St. Johns River, and they are living in fresh water.

After starting my research on the salinity tolerance of stingrays, I soon realized why people were so amazed to hear of a freshwater stingray. Stingrays belong to a group of cartilaginous fish known to biologists as elasmobranchs, which includes all known species of sharks, skates and rays. Unlike the bony fish (that is, bass, grouper, trout, etc.), elasmobranchs have a skeleton composed entirely of cartilage, a material that makes up the ends of our noses and ear lobes. Overall, elasmobranch fish do not venture into freshwater environments; there are approximately 1,000 elasmobranch species, and only about 50 have been reported to occur in fresh water.

The freshwater stingray in Florida happens to be on of those 50 species. Calling the stingray that lives in the St. Johns River “the Florida Freshwater Stingray,” however, would be a misnomer. In actuality, it is the same species of stingray that is found all around Florida’s coastline (except parts of the Keys). It is the same species that inspires cursing from fishermen and groans from beachgoers who shuffle their feet across the sandy bottom to prevent being stung. The Atlantic stingray (Dasyatis sabina) is one of the most commonly encountered rays along Florida’s coastal waters and is known to foray into freshwater rivers during the warm summer months in other parts of its range. However, the St. Johns River populations are unique because they are the only known populations of the Atlantic stingray that reproduce and complete their life cycle in a freshwater environment.

Read what else UF's grad student Peter Piermarini has to say.