Boaters stunned as giant elusive sawfish surfaces off Florida coast

A massive sawfish has popped up to say hello to some boaters who filmed the normally elusive creature splashing about in waters off the Florida Keys.

Estimated to be more than 4m long and weighing nearly half a tonne, the giant ray fish breached the tepid waters on the edge of the Mexican Gulf.

It's hard to gauge the size of the fish in the video uploaded to YouTube on Tuesday as it swam beneath the water like a formless grey and white spectre.

But when the sawfish's rostrum protruded from the water to show off its dozens of teeth it proved a shocking and marvellous sight for the pleasure cruisers.

In the same fish subclass as sharks and rays, the reclusive sawfish can grow more than 7m in length.

Their long, tooth-lined bills, known as a rostrum, once fetched thousands of dollars as a trophy.

But overfishing and hunting forced the US government to add the sawfish to the endangered list in 2003.