The dumbest animal with the biggest appetite?

A self confessed “blonde doing a stupid thing” by hand-feeding (apparently one finger at a time!) tawny nurse sharks in Australian waters, discovered she could go even further in proving her stupidity by stating:
“We’re not meant to be in the water ... if we were we’d have gills.” 
Are we human beings becoming so removed from nature that we no longer recognise that marine animals such as whales, seals, dolphins, dugongs, sea snakes, crocodiles, sea spiders, along with countless other creatures, can do quite well in the water without gills? That is to say, they could, until we unleashed anthropogenic changes. Eutrophication, ocean toxins, marine debris (80 per cent of which is plastic) all are devastating the marine environment and the food web.
In the “stupid blonde’s” defence, at least she said she’d learnt “to respect marine life”. If only the rest of us would!
SD