During a trip on the ship "Spirit of Freedom", we traveled 120 miles out from the east coast of Australia to an undersea mountain known as Osprey Reef. Rising seas left the mountain below sea level but its coral reef rose with the water. Now the walls of the mountain, and the reef on top of it, are rich in life.
At the North Horn of the reef, sharks gather to see what the current will bring. Often they are joined by divers there to see the spectacle of dozens of circling sharks and their friends the Potato Cod (giant groupers) and many other animals. You'll notice many remoras that have attached themselves to the sharks; a nearly free lunch.
On this dive the sharks were offered some frozen tuna heads and some divers; they chose the tuna. An estimated 70 million sharks are killed each year, mostly for shark fin soup (hooray for California banning it this year). The depletion of a top predator is wreaking havoc with ocean ecosystems. Hopefully wisdom will start to prevail so these graceful animals can be restored to their proper roles. Sharks breed slowly, so refuges like Osprey Reef are critical for allowing them peace to reproduce. We saw a few species: White-tip Reef Sharks, Grey Reef Sharks, Silvertip Sharks, and Black-tip Reef Sharks.