Atlantic stingrays
... that the Atlantic stingrays living in St. Johns River, Florida, are the only permanent freshwater population of cartilaginous fish in North America?
... that the <b id="mwC8k"><a href="./Atlantic_stingray" id="mwC8o" rel="mw:WikiLink" title="Atlantic stingray">Atlantic stingrays</a></b> <i id="mwC8s">(pictured)</i> living in <a href="./St._Johns_River" id="mwC8w" rel="mw:WikiLink" title="St. Johns River">St. Johns River</a>, <a href="./Florida" id="mwC80" rel="mw:WikiLink" title="Florida">Florida</a>, are the only permanent freshwater population of <a class="mw-redirect" href="./Cartilaginous_fish" id="mwC84" rel="mw:WikiLink" title="Cartilaginous fish">cartilaginous fish</a> in North America?