Off to explore the Great Barrier Reef and Osprey Reef north from Port Douglas.

Expeditions last for 6 days and nights aboard the Undersea Explorer liveaboard dive vessel

The first day is an exploration of Ribbon reef dive sites, most likely including the Cod Hole and Pixies Pinnacle then overnight to Osprey Reef

Osprey Reef is an oceanic seamount rising from the ocean floor 1000 metres below with steep walls and incredible abundance of large pelagic fish and sharks

After getting used to the oceanic diving it's time for shark action. No need to feed here, the sharks are permanent residents. North Horn is at the point of Osprey Reef where currents meet to provide food for a food chain from schools of fusiliers to spirals of barracuda and tuna and of course the sharks

Diving at Osprey Reef provides predictably clear water and huge soft corals on the vertical walls

After the dive its time for the researchers to catch a few sharks and bring them aboard for measurement.

Then it's more dives off the wall, maybe to check out the cave formations

 An ideal opportunity to pat a shark!

Back to the overnight mooring and time for a night dive - maybe even a 'black water hang' to check out the plankton life with big lights in over 1000 metre deep water. Very exciting!

Up in the morning to retrieve the nautilus for marking, measurement and release.