Endemic Marine Species of Southern Australia

When people think about scuba diving in Australia, they often picture the Great Barrier Reef, with its colourful fauna and tropical waters. Although these species are beautiful to witness, the majority are commonly found throughout the entire Indo-Pacific region. Angelfish, hawksbill turtles, and anemonefish will be consistent on your dives in a range of locations, from Thailand, to Indonesia, and even Queensland. In order to discover some uniquely Australian marine life, you’ll need to redirect down south, where you’ll find a plethora of weird and wonderful endemic species. Although the temperate waters might require a slightly thicker wetsuit, exploring the southern coast of Australia shouldn’t be missed. It is home to an abundance of rich and vibrant marine life, and highlights just how wonderfully diverse the underwater world can be.

Leafy Sea Dragon

The leafy sea dragon (Phycodurus eques) is one of South Australia’s most famous and treasured residents. They are part of the Syngnathidae family, which means they’re closely related to both seahorses and pipefish. Leafy sea dragons, or “leafies” as locals call them, are remarkable to observe underwater. They are adorned with branching, leaf-like appendages, which makes for impressive camouflage amongst kelp and seagrass. When it comes to offspring – the dad’s play a huge role. Like their seahorse cousins, male leafies fertilise and carry the eggs under their tail. This is a very unique characteristics, as biologically females are typically responsible for childbearing and care. Nonetheless, the dad’s responsibilities are dissolved as soon as the babies hatch. From then on, they no longer receive parental care. We are so lucky to have leafy sea dragons living in our local waters, but they can be tricky to find! So, go slow and look carefully.

Dive Location: The Bluff (Victor Harbour), Second Valley and Rapid Bay

Endangered Status: Near threatened

Australian Sea Lion

The beautiful Australian sea lion is one of the most playful and delightful marine creatures. They are endemic to our shores and can be found along the southern and western coast of Australia. Unfortunately, these sea puppies were historically hunted for their fur, and are now classed as “endangered” by the IUCN global rating. Australian sea lions congregate in colonies, each of which is genetically different from other populations! Reproduction is essential due to their endangered status, and breeding cycles only occur once every 18 months. The death of a single female can have devastating repercussions, especially if the colony’s population is already dwindling. Australian sea lions are pinniped mammals, and so mothers nurse their offspring with milk – just like humans! Their diet includes fish, crustaceans and cephalopods. If you see them on a dive, you’ll be surprised at how inquisitive and playful they can be. They will curiously approach you, want to play, and even cheekily nibble your fins! Australian sea lions are facing a range threats, including commercial fishing and pollution. Gillnets are detrimental, as sea lions and other marine species are caught accidentally as by-catch.

Dive Location: Fleurieu Peninsula, Yorke Peninsula, Eyre Peninsula, and even at local jetties if you’re lucky!

Endangered Status: Endangered

Australian Giant Cuttlefish

The Australian Giant Cuttlefish (Sepia apama) is part of the Cephalopod family and is the biggest cuttlefish species. They are one of the craziest, most alien-like creatures you’ll find in our local waters. These guys can grow up to 60cm in length and weigh 5kg! The best time to see them is during the spawning season (May-August) where tens of thousands of cuttlefish aggregate in the shallow waters near Whyalla, on the Eyre Peninsula. This is an incredible natural event to witness, as male cuttlefish compete for the females’ attention. To do this, they put on a kaleidoscopic colour and shape-shifting display. Using their chromatophores (specialised colour-changing cells) they create wonderful patterns on their skin. Their hyper-malleable bodies allow them to change their appearance in an instance. As this takes place in 2-4m of water, the mating event can be enjoyed by snorkellers and divers alike.

Dive Location: Whyalla during mating season (May-August)

Endangered Status: Near threatened

Southern Blue-Ringed Octopus

Although other species of blue-ringed octopus can be found in many parts of the Indo-Pacific region, this species (Hapalochlaena maculosa) resides only along our southern coastline. They are part of the Cephalopod family, which includes squid, cuttlefish and other octopuses. These guys may be tiny, but their venom is extremely potent, and an anti-venom is yet to be invented. The southern blue-ringed octopus can be recognised by its noticeably vivid blue rings which illuminate when agitated. They are foraging predators and consume small crustaceans, using their venom to immobilise the prey. As long as a safe distance is maintained, blue-ringed octopuses are not a threat to humans. They are only a potential threat when they feel attacked, so remember to maintain passive interaction when observing these fascinating molluscs.

Dive Location: Edithburgh, Port Hughes, Rapid Bay, Port Noarlunga

Endangered Status: Unknown

Port Jackson Shark

Port Jackson shark (Heterodontus portusjacksoni) is a member of the Heterodontidae family. They are easily recognisable, due to the harness markings that cross their eyes and back, and their blunt head-shape. Port Jackson sharks will hunt for food at night, primarily consuming crustaceans, molluscs, fish and sea urchins. Although adorable, these guys aren’t exactly the poster image of sharks. They only grow to approximately 1m in length, and have flat posterior teeth used to grind hard outer shells of crustaceans and sea urchins. Another feature which sets them apart from many shark species is that they can feed and breathe simultaneously. Usually, sharks need to swim with their mouth open in order to filter water through their gills. Port Jackson sharks, however, can pump water through their first gill slit and out of the remaining four, allowing them to remain still.

Dive Location: Port Noarlunga during breeding season (late August-mid November)

Endangered Status: Least concern

Dive Etiquette

The underwater world of southern Australia is truly spectacular, and we are so fortunate to be able to discover these species at our local dive sites. It’s important to remember that appropriate dive etiquette needs to be maintained at all times. We are guests in the ocean and need to act accordingly. Here are some of the most important tips to remember:

  1. Passive interaction – Divers should not touch or harass animals. This causes stress and abnormal behaviour and exposes marine life to foreign bacteria. On top of that, there are venomous creatures in our oceans, which could harm you if they feel threatened. So, keep a safe distance and observe from afar!
  2. Buoyancy control – mastering your buoyancy will do wonders for marine life! Damage to the ocean floor can be detrimental to an ecosystem. Make sure you have correct weighting, hone your skills, and streamline your gear to not disrupt the animals and their habitat!
  3. Be a role model – show others how an environmentally aware diver should act! Make sure that your behaviour mirrors your ethics. Good conduct is infectious and promotes conscientiousness within our local dive community.

Photo credit: (1) (c) Map by T. Wernberg, Marine and Freshwater Research via The Conversation (2) Leafy sea dragon by Mark Oliver, (3) Australian sea lion by Denise van der Marel, (4) Australian giant cuttlefish by Stefan Andrews, (5) Southern blue-ringed octopus by Bryan Chu, (6) Port Jackson shark by Ron van der Marel