Just about every documentary about tropical coral reefs will mention the role of cleaner stations in maintain the health of the reef ecosystem. The station attendants service the reef’s inhabitants by removing parasites, tidying the edges of cuts and even entering mouths to extract scraps of food from teeth.
A few species of shrimp act as cleaners and many types of fish. Most of the fish behave as cleaner as juveniles. Cleaner Wrasse however specialise in cleaning throughout their lives and rarely take other foods. These specialists are slender fish around ten centimetres maximum length.
Banded Cleaner Shrimp and Cleaner Wrasse are tropical vagrants that establish cleaning stations on Sydney reefs over summer and autumn. These vagrants are not the only cleaning option on Sydney reefs. There is a specialist temperate cleaner, the Cleaner Clingfish.
Clingfish are some of the smallest of all fishes. Cleaner Clingfish max out at about 3 centimetres in length. All of the Clingfish have a modified pelvic fin on the underside that forms an incredibly powerful suction disk. Most use this suction disk to hold onto the sea floor in turbulent water. The Cleaner Clingfish applies its adhesive abilities to hold onto the flanks of larger fishes as it scoots around searching for parasites.
Tropical cleaning stations are usually a prominent area of coral or rock boulder. The clients remain relatively stationary next to the boulder to allow the cleaner to perform its duties. The distinctive hovering of the clients around the stations make them obvious to a passing diver.
Cleaner Clingfish also set up cleaning stations, however they are far more subtle than their tropical counterparts. For starters, the station is a usually a clump of seaweed, coralline algae or sponge and indistinguishable from the surrounding reef. Secondly, while Cleaner Wrasse are easily spotted as they circle hyperactively around their clients, the tiny Cleaner Clingfish will swim straight to fish, latch onto their sides and slowly work their way around the larger fish. When they have finished they simply detach and float back down to the cleaner station. Thirdly, the clients behave very differently. Cleaner Clingfish clients do stay in the vicinity of the cleaning station, but don’t have to worry about dislodging their cleaner and swim around in a normal fashion. I generally spot that a fish is being cleaned after thinking that it has a wound or external parasite.
One of the main features of Bare Island is a long reef that stretches several hundred metres to the west. The top of the reef is about 15 metres deep descending to around 18 metres at the sides. It is covered by sponges and other encrusting organisms and visited by many species of fish.
There are several mature Blue Gropers on the reef, each with a set segment they patrol. As I arrived at the reef a large Blue Groper dove towards me sweeping past at arm’s length. It circled in the hope I would open up an urchin or turn over a rock.
The Blue Groper was carrying urchin spines in the corner of its mouth and deep scratches on one gill plate. There was a small dark lump on its flank. After a second look I realised it was a Cleaner Clingfish.
My attempts at a photograph involved matching the spin of the circling groper to get the clingfish in the frame for long enough to grab focus. Ten twisting minutes later I had some hopes for one or two sharp images. I was especially pleased to capture one of the cleaner next to the groper’s colourful eye, a lesser but spectacular flea.
One of the key criteria for any cleaner is not to look like food. Cleaner Wrasse have a distinctive striped pattern and strangely loping manner of swimming. Cleaner Clingfish have a brilliant orange body covered in bright blue dots. They are small but certainly manage to stand out. They hardly swim and instead waft through the water like a scrap of seaweed, nothing like an agitated baitfish.
One of my favourite parts of the Sydney year is late summer when the Cleaner Clingfish lay their eggs. Unlike many reef fish their eggs stuck to a surface rather than released into the water column. The clingfish eggs are stuck to the underside of a piece of kelp, with the parent protectively curled around the clutch of eggs.
The following day was hot with bright harsh light. Half an hour’s walk produced a few squeaks from the undergrowth but no clear sightings. We finished the walk at the base of a cool shaded waterfall. I discarded the telephoto in favour of a smaller macro lens and climbed the falls to see what was above. It turned out to be more creek.
Eyes adjusting to the deep shadows along the creek bank, I spotted two Rock Warbler chicks bathing on the edge of the creek. They were small and scruffy with stubby tails, and when one flew up clumsily up the bank I could see if must have been one of their first days out of the nest. Frustrated by the short reach of the macro I edged closer. One of the chicks flew forward to land on my knee. More than a little surprised I was too slow to focus before it slipped off and flew back to its sibling. A scolding call from the slope above and they bounced away to join their parent.
It’s not unusual to see less wildlife during mid summer as breeding comes to an end and the thermometer rises. The seasonal shift demands a change in attitude, a focus on interesting wildlife encounters after all the frantic activity of spring. Quality more than quantity.
Odds and sods