THE VAST MAJORITY OF Australia’s diving, especially for foreign tourists, takes place in the north-east, on the Great Barrier Reef. Having spent most of my dive career photographing and researching coral reefs and their inhabitants, however, I decided to explore what the country’s cooler waters have to offer.
Halfway down the east coast, the underwater environment changes dramatically. The minimum temperature at which corals can survive is surpassed, and their dominance comes to an end.
Moreton Bay off Brisbane acts as the southernmost limit for many tropical species, not just corals. It’s a mixing pot for tropical and temperate species – many of the latter exist at the northern edge of their range here, too.
The arrival of manta rays for the summer months and grey nurse sharks for winter makes for some great diving, and a good starting point for my road trip.
Diving in cooler waters can be more hit-and-miss than the tropics, as British divers will agree, but when it’s good, it’s amazing. Fish Rock Cave provides the perfect example. This tiny islet a couple of miles off the coast midway between Brisbane and Sydney is considered as lying within the warm temperate marine realm, but the temperature can vary hugely because it’s so near the continental shelf.
I once visited in February, and while the air temperature was in the 30s the water was a frigid 15°C! On this trip, luckily, we are blessed with 26°C water and great vis.
The water might be warm on this trip, but corals cannot survive below around 18°C and, apart from one or two resilient species, are not seen this far south.
The major draw here is a year-round aggregation of grey nurse sharks, set against the backdrop of Australia’s longest underwater cavern, 120m in length.
Fish Rock Cave is accessed from South West Rocks, a small town about 45 minutes by boat from the dive-site. RIBs are often used to access ocean sites in southern Australia and are exposed to the elements and not necessarily designed with comfort in mind. Expect a bruise or two, and bring a waterproof jacket to cut out that chilling wind.
The good thing is that most boats supply soup, tea, coffee and lollies between dives for some warmth, and to replace expended calories.
Fish Rock Cave is one of my favourite dives. It’s pretty special to reach the cathedral-like shallow part of the cave at 14m, having entered from the deep side at 28m. If you’re lucky, the open space of the shallow entrance will be chock-a-block with up to 40 grey nurse sharks.
This species is often kept in public aquaria because of its “terrifying” appearance, but the many needle-like teeth are in fact adapted to catching small fish, and they pose no danger to humans.
As well as these Fish Rock celebrities there are plenty of other creatures to look out for. I have seen schooling golden cow-nosed rays, eagle rays, loggerhead and hawksbill turtles, wobbegong sharks and lots of schools of smaller fish.

MOVING SOUTH, we begin to see Australia’s unique creatures taking over the eco-systems. Before planning our trip I had been aware of several such iconic species, including seadragons and several species of shark, found only in temperate Australian waters.
As I began to research further, I became more and more excited by the sheer diversity of species found nowhere else.
The huge diversity of Australia’s indigenous marine life has evolved through millions of years of complex oceanographic and geological events.
The East Australian and Leeuwin currents, pushing warm water down the east and west coasts respectively, have largely fuelled this diversification.
The constant flow of warm water down either side of the continent acts as a barrier to the coolwater species, trapping them in the south. Much like the finches and tortoises of the Galapagos Islands, when trapped in isolation species tend to evolve into unique forms.
Muck-diving is typically considered a tropical pursuit, with Lembeh Strait in Indonesia or Milne Bay in PNG outstanding examples. However, our research leads us to investigate Nelson Bay, just north of Sydney.
A wish-list of species found only along this stretch of coast begins to accumulate in my head: blue-lined octopus, White’s seahorse, blind shark and an array of amazing nudibranchs top the list.
The blue-lined is a close relative of the infamous blue-ringed octopus but with iridescent blue lines rather than rings advertising its deadly bite. From my experience of blue-rings in Indonesia I know this could be a tough one to find, so I research the local shore dives and a site called the Pipeline seems our best bet.
Two 100-minute shore dives at high slack tide easily rival Indonesia for first encounters. Indeed, I check off my entire wish-list of critters, plus Sydney octopuses and a huge Australian numb (electric) ray.
When I mentioned my wish-list to local dive-shop owners I tended to receive blank looks. Even boat-dives are rarely guided, so research and a good eye for spotting marine critters is beneficial.

MONTAGUE ISLAND, on the coastal road between Sydney and Melbourne, is renowned for its colony of Australian and New Zealand fur seals. Like most pinnipeds they are extremely playful and eager to interact with divers.
Diving here is quite hit-and-miss, as there is no dedicated dive operator. We manage to join a group doing a land tour, and jump in while they explore the history and terrestrial wildlife of the island.
As the only two divers in the water, we receive the full attention of the fur seals. It also helps that my buddy puts on an elaborate aquatic ballet that succeeds in mesmerising them!
Beside the frantic activity of the seals there is plenty to see, including several Port Jackson sharks, another Australian endemic, patrolling back and forth along the shoreline.
I’m not sure why but the sharks seem enchanted by us, and approach within inches if we remain still.
I am able to inspect their strange comb-like teeth and the primitive horns in front of the dorsal fins, and peer straight into the eye of these prehistoric sharks.
Heading further south, we use Mornington Peninsula outside Melbourne for extended safety stops after the past weeks’ diving, completing all our dives in water no deeper than 5m, and on a couple of occasions clocking dives lasting more than 90 minutes.
I have never seen so many seahorses on one dive as here, counting 13 pot-bellied and three of the much smaller dwarf short-head varieties.
On night dives I have to be careful not to accidentally shine my torch in the eyes of the sleeping seahorses, as these sensitive animals are easily disturbed.
At another site we find 10 weedy seadragons lurking among the dense seaweed patches. These are among the largest syngnathids, the group containing all pipefish and seahorses, and have outstanding camouflage.
Despite their colouration and adornments used for disguise, they are very easy to find. I find three immediately after entering the water while waiting for my buddy to descend!
Crossing the Bass Strait to Tasmania on the overnight ferry from Melbourne, we know that we’re in for some exciting diving. Cold water, big seas and kelp are the bread and butter of Tasmanian diving, and with this shift a host of new creatures can be found.
While planning our trip, I had become very excited about a strange little fish known as the spotted handfish.
Its extremely limited range in the Derwent Estuary around Hobart, specific habitat requirements and poor ability to colonise new areas have meant that it is now at a very real risk of becoming extinct, and a rare example of a Critically Endangered fish.
I contacted Sue Wragge of Underwater Adventures while working out the logistics of observing this fascinating fish in the wild. She turned out to have a soft spot for it, and was actively involved in conservation efforts to protect it.
Handfish are like a prototype anglerfish, having split from that lineage many millions of years ago and diversified around Australia’s southern coast. Their small vestigial lure is evidence of this.
At least 14 species are now known, but many from only a single or small number of specimens.
Sue takes us to three sites around the Derwent Estuary, and I find six handfish. This may sound like a lot, but between the three sites we covered virtually the entire global geographic range of this fish.

AFTER OUR SUCCESSFUL DIVES in Hobart, we make the relatively short drive down to the Tasman Peninsula, south-east of the city. The region is well known for the derelict jail at Port Arthur, which has a great ghost tour for historic thrill-seekers.
We, however, are in search of some of Australia’s last remaining kelp forests. Sadly they have been declining in size over the past few decades as a complex barrage of climatic and inter-species interactions have taken their toll.
Bays once rendered unnavigable by dense kelp growth are now almost devoid of the giant algae.
The diving, however, is very rewarding and we are even escorted to one dive-site by dolphins, seals and a lone albatross.
Beneath the waves we are in search of the famously colourful Tasmanian weedy seadragons. Despite being the same species as those in Melbourne, their southern counterparts are larger and much more vibrantly coloured.
Among the undulating algae, and quite uncharacteristically for so late in the summer, we find a pregnant male with a clutch of bright pink eggs stuck to his underside. It’s good to see that some elements of the eco-system are more productive than expected.

THE FINAL DIVE of our road trip, before the epic drive back to Brisbane, is Cathedral Caves, Tasmania’s largest sea-cave system. The bottom is at about 20m, and the openings very large and spacious, so it’s by no means a technical cave dive.
Lush, colourful invertebrate growth covers the dark walls of the caves and, provided the swells from the southern ocean aren’t prohibitively big, Cathedral Caves is a great dive.
While the Great Barrier Reef is the training ground for many divers, and surely one of the most dived locations in the world, I maintain that the real gems of Australian diving are in the south, and well worth making a trip for.
This is more challenging diving, but the rewards are great and the diversity of unique creatures second to none.