THEIR STRANGE EYES WATCH ME through the glass of the tank as their tentacles pulsate rhythmically, powering themselves about in the water. Their striking brown-striped pearly white shells gleam in the lights of the cabin, reminding me of the perfect beauty that nature so often produces of its own accord. Undersea Explorer, www.undersea.com.au
I stare, transfixed, at this fossil from the deep, the 500-million-year-old nautilus.
Im sure youre all familiar with the pattern and shape of the shell of the nautilus, the only member of the cephalopod family to have an outside shell. Essentially the nautilus is an octopus in a shell, although its biology differs in various ways, one big difference being that it has more than 90 tentacles! A ninetyopus, perhaps
Five hundred million years ago, when sharks and fish were just starting to evolve, nautiloids ruled the oceans. Made up of a vast range of species, some more than 2m in diameter, these ancient cephalopods were the giants of the underwater world.
However, at the end of the dinosaur era, 65 million years ago, most nautiloids became extinct, leaving our present-day nautilus surviving in deep coral-reef environments.
Due to the evolution of sharks and fish as visual predators, nautilus were driven to lower-light environments. They now inhabit coral-reef walls in the Indo-Pacific area at depths from 150-800m, the threat of shell-implosion preventing them from descending any deeper.
Although nautilus is such an ancient species, very little research has been carried out on its lifestyle, reproductive patterns and distribution. Undersea Explorer, a liveaboard operating out of Port Douglas in Australia, is trying to find out more through its weekly research on those living on Osprey Reef, to the east of the Great Barrier Reef.
Undersea Explorer was founded in 1995 by John Rumney to harness the tourist dollar to fund research and conservation. He believes that research leads to awareness, which then leads to conservation and best practice for the environment.
UE runs weekly liveaboard dive trips to the Barrier and Osprey Reefs, as well as providing a platform for many different kinds of underwater research.
It is the only dive-boat in Australia directly funding marine research, and gives up more than Au $40,000 revenue per year to achieve this.
Each week a marine biologist comes on board, and usually a marine researcher working on his or her own project in conjunction with UE.
One of the best parts of going on a UE trip is that you can be part of the research yourself, find out more about the reef through the daily lectures (dont worry, theyre informal and voluntary) as well as enjoying some of the best diving in the world.
THE UE NAUTILUS RESEARCH aims to find out more about the distribution, reproduction and possible migration of the nautilus through genetic research, as well as its growth rates and physiology.
The genetic research aspect is particularly important on an international level. Nautilus is a non-trading product but illegal fishing for
its shells is damaging populations in Indonesia, making finding out more about its reproduction and migration patterns a matter of utmost importance.
So how does UE carry out this research Picture a big lobster pot, a couple of kilos of steak and 300m of rope and youll get the basic picture!
Nautilus make vertical migrations at night, following the plankton and zooplankton making the same journey. So these creatures, which spend their daytime at 700m, travel up to around 300m every night, which is the best time to catch them!
One night on each trip, while moored at Osprey Reef, the resident marine biologist shows the guests how to bait the nautilus trap (when we were aboard the bait of choice was steak, as they had apparently gone off chicken!) and then set it. In the morning, you go back out on the RIB and collect the traps.
The steak must have been good, because we caught an amazing 24 nautilus! The average is 12-14, sometimes fewer.
Throughout the day the nautilus are kept in cooled, darkened, aerated tanks, emulating their usual environment of 18C at depth. We spent a normal day diving, with a chance for some nautilus photo-opportunities for those who wanted them. Being the wife of an adventurous underwater photographer led to some rather difficult posing for me - topless and surrounded by sharks while I frantically attempted to hide my modesty with two nautilus!
Back on board in the afternoon, we sit down with our marine biologist, Karl Jesienowski, to find out more about these amazing creatures. We watch them in a viewing tank, seeing how they move and discussing their physiology.
Although nautilus belong to the cephalopod family, they are the only order with an external shell.
This consists of a series of chambers laid down as the animal grows and then sealed off, connected only by a tiny tube that allows the animal to control its buoyancy. Those 90 tentacles have no suckers, in contrast to other members of the cephalopod family.
Another difference is that nautilus eyes are not nearly as developed as those of other cephalopods, reflecting their deepwater low-light lifestyle. To make up for this, some of their tentacles are for sensory purposes. We watch as they extend longer, thinner tentacles to feel their way around the edge of the tank.
Nautilus swims by sucking in water and pumping it out to propel itself backwards. Given the size of the animal, this makes their vertical migrations even more amazing. Inside, the nautilus has
a calcified beak with strong muscles, allowing it to munch on crustaceans.
We then begin to measure and mark the nautilus. This includes recording the width, length and circumference of the shell, as well as any markings or damage.
The shell is then engraved with an identification number, which is coloured with black marker and sealed with nail varnish. And no, it does them no harm at all!
THE NAUTILUS CAN SURVIVE for more than 30 minutes out of the water by sealing itself with its brown hoods, as you can see from the pictures. UE also has a high incidence of recapture, proving that the engraving process does not harm the animal. This recapture allows UE to monitor growth rates and any changes in the shell.
For example, on our trip we recaptured a nautilus the shell of which showed signs of recent damage, prompting speculation on what could have happened to the animal.
We know that sharks are a predator for the nautilus - could this particular one have had a narrow escape
Undersea Explorer has now caught and recorded more than 2150 nautilus, and constantly monitors the data for patterns and changes. Being a part of this research was a brilliant experience.
I have always thought the shells of these animals so beautiful, but never known what inhabited them!
It was wonderful to be part of a liveaboard that is giving something back through research, as well as educating divers on the fragile environment we enjoy so much. The nautilus research is only a tiny part of what UE does, so if you want to find out more about other creatures and issues it is addressing, go and see for yourself.
In the words of John Rumney: We are the best dive-boat - period. Then we also save the planet. And the best thing is that any diver can be a part of that.