Byron Bay - Where Tropical and Temperate Waters Merge

Contributed by Wandy Hochgrebe

The township of Byron Bay lies on the east coast of the Australian continent, a mere two hours south of Brisbane and about nine hours north of Sydney. Byron Bay is quite well known for being the most easterly point of the Australian mainland and is home to the most powerful lighthouse in the southern hemisphere.

Known for the alternative lifestyle and friendly people, Byron Bay has grown into one of Australia's most popular holiday destinations for people wanting something more than beach alone.

The many cafes and the relaxed atmosphere put you in a holiday mood right away. For those seeking culture, nightlife and fine dining, Byron also has a lot to offer. Art exhibitions, gallery openings, fire dancing performances and plenty of live music are always on offer.
People do not only visit Byron Bay for its culture it also has some major natural attractions. One of them is the annual whale migration of the majestic Humpback Whale.Between May and October 5000 individuals make their way up North and back down to the Antarctica each year. Both land based whale watching and the close-up experience from boats has increased in popularity over the last few years.

Although Byron Bay is one of Australia's most popular holiday destinations, only few people realise the fantastic marine environment Byron Bay has to offer. This popular subtropical township renown for its beautiful beaches and stunning hinterland is part of the Cape Byron Marine Park and home to the Julian Rocks Marine Sanctuary.

Julian Rocks

Julian Rocks consists of ancient igneous rock, remains of a volcanic eruption more than 20 million years ago. It is an extension of Cape Byron separated by water and forms a most unique habitat, providing shelter and food for more than 500 tropical and temperate fish species alone. Boulders, sand gutters and trenches form a fantastic underwater landscape, coloured by sessile life such as sponges, hard and soft corals and tunicates.

Since 1982, marine life has been protected to a certain extent through the creation of Julian Rocks Marine Reserve. This helped the emergence of a unique underwater Mecca for marine life at this rock formation only 2.5km off shore.

In December 2002 Julian Rocks became part of the Cape Byron Marine Park and in May 2006, the Marine Park zoning plan came into action, which amongst other things means that an area with a radius of 1500m around Julian Rocks has become a Sanctuary Zone for most of the year. This will hopefully see fish stocks increase even more and give the critically endangered Grey Nurse Sharks some well deserved additional protection.

Even though Julian Rocks looks rather small, dive sites are plenty and its rocky reefs extend to Spot X, Mackeral Boulder and the Cape Pinnacles. Diving is pleasant all year round with temperatures ranging from 18˚ C in winter to 27˚ C in summer. Due to its sheltered location diving takes place almost every day of the year, with visibility ranging from 5 to 30 meters.

The marine environment around Byron Bay is quite unique as both tropical and temperate currents that flow past Julian Rocks contribute equally to the abundance and variety of marine life. With water temperatures and currents changing throughout the year there are many seasonal visitors. Every dive at Julian Rocks is different unlike diving on many coral reefs and many people return to this dive site on a very regular basis to experience it during different seasons and conditions.

Winter - Grey Nurse Sharks

The month of May, when water temperatures start to drop, marks the start of the Grey Nurse Shark season. These endangered and in NSW fully protected sharks are fantastic to encounter. Although these sharks look ferocious they are perfectly safe to dive with.
The Grey Nurse Sharks (Carcharius taurus) prefer the deeper waters and they often congregate in the sandy gutters on the North side of Julian Rocks at a depth of around twenty meters.

Through the 1950s and 60s these sharks were hunted to near extinction in Australian waters as they were wrongly believed to be man-eaters. With their total population estimated to be less than 500 the Grey Nurse Shark population on the East Coast of Australia is now considered Critically Endangered. Fortunately, Julian Rocks has been identified as one of thirteen Critical Habitats for Grey Nurse Sharks along the NSW coast. Some fishing and even dive behavioural guidelines were put in place in the hope this will increase the chance of survival of this species.

Spring

In spring when the water temperature starts rising, a variety of tropical species become more common around the rock and different kinds of butterfly fish, angelfish and surgeonfish dart around the coral outcrops that can be found in different places.

The juvenile Half-circled Angelfish (Pomacanthus semicirculatus) can be easily identified due to its bright blue colouring and white semi-circles on the side. Once it becomes an adult the rings disappear, but they are still stunning. Of the Surgeonfish the Blue Tang (Paracanthurus hepatus) must be the most noticeable one and juveniles can be found hovering just above table corals together with Headband Humbugs (Dascyllus reticulatus), ducking inside for cover as soon as anything approaches.

The butterflyfish are less shy and are found mostly in pairs, nipping on coral polyps or grazing. The Threadfin, Vagabond and Dusky Butterflyfish (Chaetodon auriga, C. vagabundus and C. flavirostris) are some of the species common at Julian Rocks. By the way, don't cross into the territory of the Girdled Scalyfin (Parma unifasciata) as those little farmers are fierce in protecting their algae patches.

Of course everybody knows the anemonefish, which live in symbiosis with their anemone. At Julian Rocks a number of different species can be encountered, the most common ones being the Barrier Reef Anemonefish (Amphoprion akindynos) and the Blue-lip Anemonefish (Amphiprion latezonatus).

Around mid December the anemonefish start laying their bright orange eggs. Interestingly, the eggs are cared for mainly by the male, which can be found fanning the egg mass with their fins, providing its offspring with oxygen rich water. Hatching generally occurs after a period of 6 to 10 days.

It is at this time that the large stingrays arrive. Black Stingrays (Dasyatis thetidis), the Cowtail Stingray (Pastinachus sephen) and the Smooth Stingray (Dasyatis brevicaudata) can be seen on most dives. With their huge wingspan of almost 2 meters or more they are a quite impressive sight.

Summer

As the water temperature starts to reach its maximum in early January, Leopard Sharks (Stegatosoma fasciatum) aggregate at Julian Rocks.
Very little is known about these prehistoric looking and mysterious sharks. They mainly lie together in small groups on sandy patches and can be easily recognised by their round forehead, pale skin with leopard-like spots and their characteristic tail.

Leopard sharks are egg-laying sharks, but no egg cases have ever been found near Julian Rocks. Much of the biology of the leopard shark is still unknown including where the individuals found at Julian Rocks go in winter and whether the same animals return to the few known aggregation sites each year. As the water begins to cool in early May the Leopard Sharks simply disappear from Julian Rocks.

Manta Rays visit Julian Rocks on occasion, however the end of summer and early autumn seems to be their preferred time of the year.

Other Sharks and Rays

The most commonly observed shark around Julian Rocks is the wobbegong shark. Three different species have now been identified and they are present all year round.

The Dwarf Ornate Wobbegong only grows to one metre and is the smallest species. It is observed regularly in the shallower waters, draped over a sponge or table coral. The larger Ornate Wobbegongs are not as common in this area as the other two species. It has only just recently been decided that this is a separate species from the Dwarf Ornate Wobbegongs and they can grow up to 3 metres in length.
The similar looking Spotted Wobbegong can be distinguished from the Ornate Wobbegongs by its colour patterns, which consist of broad dark saddles and the distinct circles formed of groupings of small white dots.

Most of the time the wobbegongs lay at the bottom and feeding occurs mainly at night. Their prey includes fish, crayfish, crabs and octopus.
Closely related to the sharks are the rays, most of which are regulars at Julian Rocks.

Although the Blue Spotted Stingray (Dasyatis kuhlii) is believed to be a solitary species, these rays seem particularly active in summer and can be found in the shallows, piling on top of each other in the sand. Hundreds of Blue Spotted Stingrays can be observed in very tight groups in the same area, usually in early to mid January which could be interpreted as mating behaviour.

Another ray species seems to have found a meeting place at Julian Rocks as well. The Numbfish (Hypnos monopterygium), also called Electric Ray, becomes visible in higher numbers during the beginning of autumn in March. Normally they bury themselves in the sand and wait for their prey to swim past, but during this time they actively swim around in the shallows. This behaviour has been observed during the same weeks of the year for many years at Julian Rocks and has not been reported elsewhere.

These odd-looking rays have specialized muscles located on their back which can generate a significant electric current (50 amps, with peak of pulses sometimes exceeding 1 kilowatt). Not only does the Numbfish use this to stun their prey; it can also seriously deter any predators.
Julian Rocks' reefs are also home to the White-spotted Eagle Rays (Aetobatus narinari), the Sparsely Spotted Stingaree (Urolophus paucimaculatus), the Eastern Fiddler Ray (Trygonorrhina fasciata), the Eastern Shovelnose Ray (Apytychotrema rostrata), the Giant Guitarfish (Rhynchobatus djiddensis) and very occasionally the Southern Eagle Ray (Myliobatis australis). And if you are very lucky you can witness spectacular schools of up to 200 Cow-nose Rays (Rhinoptera neglecta) that sometimes pass by Julian Rocks.

Marine Turtles

One of the big attractions when visiting Julian Rocks must be the friendly sea turtles that live here. Julian Rocks is home to three different species: the Green Turtle (Chelonia mydas), the loggerhead turtle (Caretta caretta) and the Hawksbill Turtle (Eretmochelys imbricata).
All three marine turtle species are currently experiencing serious threats to their survival.

Not many people know that adult Green Turtles are unique among sea turtles in that they have a completely vegetarian diet and feed on seagrasses and algae, whereas Hawksbill Turtles feed mainly on invertebrates like sea squirts and anemones.

Most divers know that Loggerhead Turtles can reach enormous sizes. One very large Loggerhead seems to call Julian Rocks its home. Its size indicates that it must have been around for a long time! The lifespan of a Loggerhead turtle is estimated to be 50 years or more and adults grow to an average weight of about 100 kilos. Equipped with powerful jaws they can crush crabs and molluscs and even the spines of a sea urchin are no defence.

Even though turtles are very much at home underwater they are in fact reptiles and need to go the surface to breathe. During resting periods they can stay submerge for long periods of time. If they become more active they will need to return to the surface more often - which is why turtles are very commonly seen by snorkellers. Julian Rocks therefore not only attracts divers, many people that have never ever snorkelled in their life come out here to swim and snorkel with turtles ... and some of them will turn into divers eventually.

Cephalopods

The rocky reef provides an ideal habitat for many Cephalopods - literally meaning head-footers -, which include octopus, cuttlefish and squid.

Several species of octopus have been sighted on the reefs around Julian Rocks. Generally shy creatures these invertebrates prefer to crawl into their burrow when they feel threatened, holding shell fragments and rubble in front of them.

The cuttlefish around Julian Rocks can be found hovering just above the ocean floor, and usually move around in pairs.
When cuttlefish feel threatened they initially might try to blend in with their surroundings and almost disappear from sight. They are true masters of camouflage. If approached too close for comfort they will try to make themselves look as large as possible by extending their arms and rapidly flashing colours are displayed often as a warning.

Another member of the cephalopods, the squid, is seen around Julian Rocks only occasionally. Like the other cephalopods they use a specialised foot called a siphon, which enables them to hunt and escape quickly by expelling water under pressure.

Pelagics and Predators

Marine life does not only come to find shelter at Julian Rocks, food is abundant here attracting schools of streamlined predators. Pelagic hunters such as Mulloway (Argyrosomus japonicus) and Yellowtail Kingfish (Seriola lalandi) are fast swimmers that can be found regularly in the deeper waters around Julian Rocks. Other pelagics include Big-eye Trevally or Jacks, as well as Golden and Blue-fin Trevally.
Occasionally barracudas pay a visit to the rocky reefs and can be seen in small schools out in the blue.

Hunting closer to the reef are the spectacular lionfish. Several species are observed in this area including the Common Lionfish (Pterois volitans), the Dwarf Lionfish (Dendrochirus brachypterus) and the Spotfin Lionfish (Pterois antennata). It is common diver knowledge that Lionfish have extremely venomous dorsal fin spines, but they are generally not dangerous to approach. Lionfish prey on a wide variety of smaller fishes, shrimps and crabs. They have few predators in their native range. Their prey, which is hunted mainly at night is obtained with a lightning quick snap of the jaws and swallowed whole.

Several species of moray can be found at Julian Rocks, including the Abbot's Moray (Gymnothorax eurostus), the White-eyed Moray (Siderea thyrsoidea), the Green Moray (Gymnothorax prasinus), the Mosaic Moray (Enchelycore ramose) and the Sieve-pattern Moray (Gymnothorax cribroris).

Moray eels can look quite fearsome, as their mouths are equipped with razor sharp teeth. The wide open jaws are generally not a sign of aggression, the gape is necessary for respiration as water has to be actively pumped across the gills. During the day most morays are found in crevices and holes affording protection from predators and allowing them to strike at prey from a hidden position.

Besides the animals mentioned already there is plenty more to see such as the playful Blue Gropers, bullseyes, fusiliers, Old Wives, Harlequin Ghost Pipefish, Pineapplefish hiding under ledges, Sergeant Majors, Barred Soapfish, cowry shells, a variety of brightly coloured nudibranchs, and plenty of other molluscs, crayfish and an array of smaller crustaceans. Sometimes there are so many fish you can hardly see where you are going.

Byron Bay and Julian Rocks offer a unique environment that celebrates and nurtures diversity, abundance and colour and is considered one of Australia's top 10 dive sites - and of course our number ONE.

In addition to the amazing wildlife that can be encountered at Julian Rocks, this diving site also has the advantage that it is only a short boat ride from the shore. You can do up to four dives a day, but it is also possible to do just one or two; leaving plenty of time to relax and enjoy Byron Bay or explore the surrounding national parks and villages.

Diving is done on a small scale and there are only two dive shops in town, which ensures that the dive sites are never crowded.

Getting there

Obviously you can just drive to Byron Bay: ~200 km south of Brisbane and 850 km north of Sydney. Byron Bay has also two airports nearby: one at Ballina (20 minutes south) and one at Coolangatta - Gold Coast (40 minutes north). There are regular flights from all Australian capitals and some international flights into Coolangatta. Brisbane Aiport has flights from and to destinations around the world.

Photos and video clips by Tim Hochgrebe from Planula Underwater Productions. More videoclips from Tim Hochgrebe can be found at You Tube.

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