Occurrence at the Busselton Jetty:
The net-patterned jellyfish is commonly sighted during the cooler months of autumn and winter from the top of Busselton Jetty should you happen to look over the edge. Both adult and juvenile specimens can be seen. However it is only occasionally seen from the Observatory windows as these poor swimmers are washed past by the waves and swell. In the instance of observing a net jellyfish from the Observatory windows, sometimes juvenile Mosaic Leatherjackets can be seen taking shelter amongst the jellyfish tentacles.
Net-patterned Jellyfish are a distinctive species of the phyla Cnidaria (ny-dare-ea) Class Scyphozoa. They can be easily recognised by their single long, clubbed feeding arm which is often brightly coloured red or purple. This feeding arm is often damaged by attack or predation and in individual jellies may be seen in various stages of regeneration or not present at all. Across the rounded bell are fine dark red lines making the net pattern and sometimes the bell is covered in small warty lumps. The curved, feathered arms and bell contain stinging cells called nematocysts which can deliver a mild sting if touched. Often the gonads under the bell can be seen in the form of a white cross. The Net-patterned Jellyfish is common out on the open water to 30m depth but depending on prevailing winds and tides may be washed into coastal and shore waters. They reach around 30 centimetres length across the bell.
Edgar, G. (1997) Australian Marine Life: The Plants and Animals of Temperate Waters, Australia
Gowlett-Holmes, K (2008) Field Guide to the Marine Invertebrates of Southern Australia. Notomares, Australia