The Swan River Estuary

Gearing up on the river bank, preparing to scuba dive within the Swan River is a time of great anticipation. What am I going to discover, what amazing things will I find? I won’t be looking at the big picture, water visibility limits your perspective and to make the most of your time you need to look small. Despite the fact that I have dived all around the world, the Swan River Estuary is still one of my favorite dives, with a macro lens and keeping your eyes focused on the small, you can come across amazing creatures. Some of the best shore dive locations, from an underwater photographer’s perspective, are around Blackwall Reach in Bicton, The Coombes in Mosman Park and Rocky Bay in North Fremantle.

Decorator crab

The rocky outcrops harbour much life, covered in sponges and with many nooks and crannies, there is plenty of opportunity for creatures to hide. Decorator crabs with their bodies completely covered by sponge and coral growth, scurry among the sponges, unless you see them move they just resemble another sponge or coral.


Sea horses hang by prehensile tails wherever they can get a grip, I have found one of the most reliable locations to search for them on the artificial “rocky outcrops” that are the boat moorings around deep sections below the cliffs of Blackwall Reach. On one particular dive I was following the mooring rope down to the bottom and just near where it was tied off at the base, among the tumble of rope was a tiny juvenile seahorse only around 5cm long. It was so small that its snout still held some transparency. But the most amazing discovery came after I looked at the photo later on my computer and found on the curve of its back a miniature anemone had decided to get a free ride. This image became one of my collectible limited editions… “Seahorse.

Purple Malu

Other discoveries among the rocks and moorings are beautiful tube worms, either solitary or colonial groups, that spread their fronds into the water column, filtering out the food particles as the current passes by. Shrimp mass together in the crevices and cracks, peering out at you but scuttling back when you get too close. Incredible nudibranchs which are flamboyant but distant underwater cousins of your average garden variety slug, but unlike the slug, these molluscs are far from plain and grey. Their name is derived from the Latin words for naked gill, which grow as a delicate filigree of lace like structure that protrudes from their back. Nudibranchs come in such diverse variety of colour and shape that they are a favourite find of mine, stunning when photographed in an abstract composition.

Sea-grass beds are incubators of life, tiny fish and shrimp hide within the fronds, sea horses again can be found moving through the grass, possibly hunting for mysid shrimp and tiny life. Blue-manner crabs hide only to suddenly throw up their claws at you as you get too close, if you are not prepared as you glide over them it can scare the bejaysus out of you for a second or two.

Just beyond the sea-grass beds, where the substrate is still firm, malu anemones, with pale short pink tipped tentacles lie prostrate on the bottom. My favourite abstract of this creature is titled “Purple Malu.” A great find on some but not all of these anemones, look closely through the tentacles and you might find tiny transparent commensal shrimp, more like minuscule lobsters complete with tiny claws, difficult to see but when you do you wonder what else hides down here in plain sight.

Commensal shrimp
swan anemone
Swan Anemone

At first glance the silt bottom seems like a barren desert, but then you come across beautiful cerianthus tube anemones, often seen solitary but also found in groups, they are like a garden of alien flowers all moving their tentacles about to obtain food from the passing current.  To witness these in the best conditions it is necessary to dive at the end of an incoming tide. Almost at slack tide is when the water is most clear and you must approach and float with perfect buoyancy just centimeters above the bottom. One wrong move will create a silt out that will cover the anemone in particles and ruin any chance of a great image. My favourite print of these amazing creatures… “Swan Anemone.” Other denizens of the silt include large shrimp and more crabs that both lie half submerged in the silt, the shrimp feeding from particles within the silt, the crabs waiting for food to swim by so that it can be attacked in ambush from beneath.


Small spotted stingrays do the same, with only their eyes protruding until they explode upwards as you get too close, flying away in a slipstream of silt only to duck back under the cover of the bottom again. The silt also tends to favour the more bizarre like the fingered dragonet, a fish that walks across the bottom on spiny fingertips and flags a vibrant fin out from the top of its head. Spectacular gurnard perch glide across the silt, they are a fish with large beautifully patterned pectoral fins that extend out like the wings of a butterfly. One particular gurnard allowed me to swim above it and photograph down onto the pattern of its fin and body which then became the print “Poco.”

The Swan River is truly an oasis of marine life, other wonderful species like dolphins cruise the waterways. Beautiful copper coloured eaglerays are often seen near Point Walter, gathering in groups within the shallows. These majestic rays can grow quite large with wingspans up to a meter across.


Our river is a fragile habitat, its health completely at the behest of our lifestyle and industry. We need to protect it and fathom a greater understanding of how we impact on it. The Swan River Estuary is a magical wonderland with much to see and experience.

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