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Tuesday, 18 July 2006 00:00

Busselton Jetty

By Peter Buzzacott

Just a half-an-hour south of Bunbury lies a wonderland filled with magical creatures of every shape and colour. Long the realm of divers, this hitherto hidden world is now enjoyed by all, thanks to an engineering marvel. Yup - there is no-where in the west like Busselton Jetty.

Busselton sits in the middle of Geographe Bay, facing north, 220Kms south of Perth. The jetty's first jarrah piles were driven into the sand in 1865 and since then more have been added or replaced up till the present day, extending the jetty further from shore as the shifting sands slowly fill the bay. The much loved timber jetty currently extends about 1850m from shore and visitors are welcome to walk the length for a token entrance fee that costs about the same as a cup of coffee.

Part 1

Divers wishing to reach the end can either book a very reasonably priced boat dive through one of the local dive centres or else stroll out along the boardwalk leisurely towing their gear on a fridge-trolley ($19.95 from Bunnings). There is a new ladder and a low gearing-up platform, which is a huge improvement over the old, steep ladders braved only by the strong and determined during previous years.

Once underwater most divers head north, finning passed the new underwater observatory, a 30m round concrete marvel, with five viewing levels and 11 large windows, each one worth about $50,000 to replace, so divers are requested to stay well clear. There are better things to see underwater anyway, just metres further north, where fishing is discouraged and where the wildlife has exploded.

Every inch of untreated jarrah is a battlefield, with barnacles fighting mussels, sea-squirts fighting sponges, telestro coral fighting tangled tubeworms, in a blaze of colour unrivalled elsewhere in the bay. Between the piles large schools of yellowtail cruise, parting just enough to envelope divers, so great in number that I have had to descend and look-up from below the school to see my buddy. Long-finned pike join the party, as do Australian herring, distinguishable from the yellowtail by the black tips on their tails. Of a more sedate disposition, old wives, globefish and Shaw's cowfish hover about, each a photographer's delight. The lucky diver might even spot a pineapplefish and at night the catfish come out to feed, as do the extremely cute striped-dumpling squid and the (less cute) blue-ringed octopus.

The piles themselves are a rare treat, and a single pile offers divers the full spectrum of life, from the perilous intertidal zone where only the tough survive, through hard corals, algae, down though sponges and soft corals, to the less well-lit base, where the night predators like southern bailers and eleven-armed sea-stars pick off dinner every night. Blue-throated ascidians cluster, jostling each other as they feed, while the striking rose sponge sits quietly, unmoving. Or does it? Looking closely one can often spot the well-camouflaged rose sponge nudibranch, an almost identical twin to the sponge. Indeed the jetty is a nudibranch lovers Mecca, with half-a-dozen types easily found. Flatworms too, and tubeworms, with their delicate feeding fans splayed hopefully.

Along the top fishermen cast-in lines, ostensibly for a feed but more often killing what they catch for bait, or worse, tossing back sting-rays minus their tails, still alive and helpless. It is a sad fact that, unless you head toward the no-fishing zone, divers are very likely to come across some of our favourite and most beautiful friends, butchered. In December 1999 a 65m section of the jetty 220m from the end caught fire and fishermen have been hard-pressed to fish from the very end since, so now it is more spectacular than ever. On a good day divers might spot shovelnose rays, striped stingarees, numbfish, eagle rays and masked stingarees.

Beyond the jetty is worth a look too, if time and air permit, and with the maximum depth just 8 or 9 metres, divers are often under for well over an hour per cylinder. Here you will find large footballer sweep, flathead, the ever-amenable brown-spotted wrasse and, if you're lucky, sea-dragons (I've never seen one here but they're well documented). As hard to imagine as it is, when you've dived this kaleidoscope often enough, even the keenest divers occasionally need a change and this is when I head for the seagrass meadows to the left and right of the jetty.

Part 2

Here you will find seagrass, occasional clumps of sargassum growing their own buoyancy compensators, and sandy patches where, if you gently wash a pressure-wave downwards with your hand, you will find sea-stars buried, often on top of each other (for companionship perhaps?). Cuttlefish hover amongst the grass, sometimes you may find a samsonfish resting, John Dory warily stay out of reach, and during late summer/autumn large comb-jellies glide passed, reminding me of aliens from The Abyss. The careful diver will often spot a tiny crustacean in the middle of these transparent creatures, perhaps either a cray or a crab spawn. The sandy patches are certainly alive with blue swimmer crabs. Wireweed grows amongst the sea-grass, with many strange colonial ascidians precariously clinging to the stems for dear life.

Large mammals are often seen here too, such as the Australian sea-lions that occasionally visit, the many dolphins who live in the bay (they love crabs), or the odd whale that loses its way. A few years ago an injured long-beaked whale arrived and spent the better part of a week leaping out of the water beside the jetty before heading on up to Bunbury. Even as recently as June this year there was a mass stranding of more than 100 False Killer Whales just 2Kms south of the jetty. Well over a thousand people rushed to help and by sunset all but one of them were last seen swimming off around the cape toward deeper water (the whales that is, not the volunteers).

Speculation about the reasons for this and other strandings range from the usual, (and proven), effects of naval sonar, to disturbances in the water temperature caused by unusual winds. Geographe Bay sits to the east of Cape Naturaliste where during summer the cool Capes Current flows northward, bringing cool water into the bay, while in winter the warm Leeuwin Current flows south from the tropics, bringing warm water into the bay. Just prior to the last big whale stranding Busselton enjoyed nearly three weeks of moderate-to-strong easterly winds, perhaps driving the surface water from the bay and out to sea, to be replaced with warm water from the Leeuwin Current, causing the whales to miss their right-turn at the cape?

It's all theory at this stage but there is plenty of marine research underway in Geographe Bay, and water temperature might just provide a clue. Since 2000 the Bunbury Cathedral Grammer School have been recording water temperature changes just north of the jetty, using a Tid-bid temperature monitor. The water regularly rises to 22C in summer, and drops to as low as 15C in winter, which is still moderate thanks to the warm Leeuwin Current, which is why we get such little fog in WA. As the sun moves slowly southward for summer, and the daily solar radiation index rises, epiphytic algae colonise the seagrass, most commonly the stringy, brown filamentous Hinksia, which by March weighs more than the grass it clings too. It soon breaks up and drifts away as Autumn arrives, noticeably reducing the vis to 5 or 10m, and by late April there is hardly a strand to be found.

In June the storms arrive from the north, waves batter the jetty and some of the seaward stuff is ripped off, giving chance for new growth in the spring. Viz often drops to 10cm or so at this time, so only the hardy venture out in winter after 'a blow' (even with 'super-macro' 3-5cm focal distance, it's rubbish). After a few days of calm, if a couple of large high pressure systems roll passed to the south, the viz briefly picks up and it's a treat to get back in.

My favourite time of year though is spring, from October onwards (even September is pretty). The seagrass is producing seed, the molluscs are leaving circular sand egg-casings strewn across the floor, nudibranchs glue their attractive coils of eggs to the rubble like gay decorations, the sargassum are golden and bursting with bubbles anew, even the southern squid leave clusters of white tubular eggs swaying in the gentle surge. Amongst the grass small schools of fry clump together. Safety in numbers I guess.

Ah yes, Busselton Jetty is truly a treasure. We are lucky indeed to have such an asset in Western Australia, thanks to the tireless Busselton Jetty Environment and Conservation Society. The latest challenge they face follows an engineering report that recommended $16Million worth of restoration work. The little red train so many of us have caught out to the end of the jetty has stopped running, and a public meeting held recently considered proposals to either repair the existing 2.5m wide structure or, for the same money, to build a new 4m wide structure next to the existing jetty, removing the unstable parts and keeping the good bits for extra-wide platforms. Sounds good to me.

Essential contacts
In Busselton:
The Dive Shed - SSI Dive Centre -
Live jetty webcam - www.watercorporation.com.au
Jetty Preservation Society - www.busselton-jetty.asn.au

In Dunsborough (30 minutes south):
Cape Dive - PADI 5-Star Dive Centre -

In Bunbury (30 minutes north):
Coastal Water Dive - PADI Dive Centre -
Reef Diving - Photography, guided dives, courses -