Watery Neighbours: The Animals that Reside Beneath Australia's Waves

This is a guest post by Melissa Marquez.

With summer in full swing, it’s important that we look at the animals sharing the waters with Melbourne’s residents and visitors. After reaching the beach (and slathering some sunscreen on), don’t skip the tide pools! Here you will see sea snails, tubeworms and abalone. White rock sea snail eggs (Dicathasis orbita) have recently been found to contain chemicals (called N-alkylisatins) that are proving incredibly powerful in fighting cancer cells, as shown by researchers from the University of Wollongong.

Wading out to slightly deeper waters, there are beautiful seaweed gardens including towering bull kelp forests and beds of delicate green and red species. And while you may be hungry for some abalone, no species of these fellows are allowed to be caught from the intertidal zone in Victorian waters (less than two metres deep); Port Phillip Bay has a permanent ban on the take of greenlip abalone.

There are many species of jellyfish to be found in Australian waters. 

There are many species of jellyfish to be found in Australian waters. 

Calmer waters support colourful soft corals, sponge gardens and sea urchins. Most people become familiar with the sea urchin after plucking its painful spines from their feet. While the spiky sea urchin doesn’t look like a culinary delicacy, there is a demand for the creature in Hong Kong. Sea urchins, when not kept in check, can wreak havoc on reefs, devouring kelp and other important resources.

Also on the reef, you can see sharks, skates, and rays. There are about 180 species living in Australian waters – some of which you can read about in a previous Wild Melbourne post. They share this oceanic space with a number of species, such as the critically endangered hand fish (family Brachionichthyidae), which prefers to walk on its pectoral and pelvic fins than swim.

There are plenty of creatures to look out for while swimming in Australian waters. Living in Australia’s reefs are stinging stonefish (Synanceia verrucosa), with a mottled appearance that helps them hide. Take care not to step on the coral – not only will it help protect the reef overall, but these stonefish are extremely poisonous and hard to see! Another spectacularly coloured venomous animal is the southern blue-lined octopus (Hapalochlaena fasciata), a type of blue-ringed octopus (Genus Hapalochlaena). The box jellyfish (Chironex fleckeri) is another creature all Australians should be wary of. These venomous residents have tentacles that can dangle up to two metres long; pay attention to any signs your beach may have posted in regards to sightings of these animals.

Travelling the Great Ocean Road this summer? If you make your way to Portland from November to May, you may be able to spot some blue whales (Balaenoptera musculus) that feed on the abundant krill present at this time. Krill are small crustaceans that are the main staple in the diets of hundreds of different animals – including baleen whales, like the blue whale! If you aren’t able to see its streamlined shape (they are deep blue in colour, and have a dorsal fin located near their tail), perhaps you can still spot the tall, straight blow from its blowhole.

If you're lucky enough, you may be able to spot a blue whale in Victorian waters off Portland between November and May. 

If you're lucky enough, you may be able to spot a blue whale in Victorian waters off Portland between November and May. 

And while no human has observed these fish in their natural habitat (exceeding depths of 1,000 metres), the deep waters of Australia are home to a fish which can claim the title of “ugliest animal on Earth”: the blobfish. A member of the family Psychrolutidae, these bottom-dwelling fish look like tadpoles with really big heads. There are three types of blobfish in Australian waters: the smooth-head blobfish (Psychrolutes marcidus), the western blobfish (Psychrolutes occidentalis), and "Mr Blobby" (Psychrolutes microporos). However, although considered “ugly”, it is perhaps more important to acknowledge that they are actually not that well studied. A recent article on The Conversation detailed how perceptions of these deep sea creatures as ‘monsters’ may actually be harmful to their conservation – so perhaps we shouldn’t always judge an animal by its looks!

You may be sharing the warm sand and cool ocean with hundreds of fellow Australians and a few too many tourists, but while looking at the waves, don’t forget there are also plenty of ocean residents sharing the water with you.

Melissa Marquez is a marine biologist studying sharks, skates, rays and chimaeras in Wellington, New Zealand. You can follow her research on Twitter (@mcmsharksxx) and outreach efforts at www.finsunited.co.nz.