Swan River Marine Life

The Swan River has very little sea grass or weed and the bottom is mainly very fine silt. Though, at first glance, appearing devoid of life, marine animals congregate around wrecks, jetty pylons, and on rocks near the shore.
A range of different sponges, Phylumporifera, live on the wrecks scattered in the river.
Purple tipped sea anemones Pachycerianthus sp. are scatted on the bottom. A number of sea pens, order Pennatulacea, also live in the silt.
During summer you will see a few jellyfish, the most common being moon jelly fish, Aurelia aurita. Also during this time lookout for the jellyfish Phyllorhiza puctata. Look closely to see if any juvenile fish are living among the tentacles.
Several tube worms, family Sabellidae and family Serpulidae, including Protula sp., live on wrecks and jetty pylons.
On the silt you may see the, possibly introduced, tube worm ?Myxicola infundibulum.
Pylons are often covered in barnacles, class Cirripedia.
Western king prawns, Penaeaesus latisulcatus, can be spotted at night, remember bag and size limits apply if you are hunting. Less common in the Swan River is the smaller western school prawn, Metapenaeus dalli. If you are lucky you may find the small, almost transparent, carid shrimp Macrobrachium intermedium near the shore.
Twice I have seen paper bubbles, possibly Bullina lineata. Both times it was amongst the rocks at The Coombe. In the river I have seen one other paper bubble, which may have been Philine angasi, there are records of this species congregating in estuaries.
A number of nudibranchs, family Polyceridae, live in the river, though nowhere near as common as outside the estuary.
Cephalopods I have seen include two unidentified cuttlefish species, family Sepiidae, and one type of squid, possibly southern calamary, Sepioteuthis australis. I have not seen any octopus, family Octopodidae.
A large number of starfish, class Asteroidea, live in the river, possibly the most beautiful is Lucidia australiae with its 'pixellated' body.
The most common crab you will see is the blue manna crab, Portunus pelagicus, again bag and size limits apply. If you look closely at the wrecks you will see a number of other crab species, including decorator crabs.
I have also seen striped cat fish balls, Plotosus lineatus, under a number wrecks. At The Coombe both wrecks and one of the large buoy anchors have resident cobblers, Cnidoglanis macrocephalus, also known as estuary catfish. To be cont...

Other Animals Sharing The Swan
A number of water birds inhabit the river, including, of course, black swans, Cygnus atratus.
I have twice seen darters, Anhinga melanogaster, hunting in the river, once at a depth of 9m.
From the shore, if you are really lucky, you may see one of the rivers resident ospreys, Pandion haliaetus, soaring overhead.

You can read more about the river on this post: Swan River