by Zephem » Tue Dec 14, 2004 4:24 pm
It's really simple, and yes they can.
Certain species of sharks are unable to remain still, they have to constantly swim. When they swim, water passes through their mouths and into their gills. This is when they extract the oxygen from the water. If you stop a fish from swimming, like when you net it or tie it down, or even cut it's fin off, the shark is deprived of oxygen and dies.