19th October, 2022

Marine Life in Sydney Harbour

You will be surprised how much marine life exists in Sydney Harbour, on the doorstep of Australia’s most populous city. This natural Harbour has as much diverse topography and marine life under the water as the landscapes and foreshore above.

Sydney locals and visitors love to get out onto the Harbour for a cruise and dining experience with Captain Cook Cruises to enjoy the incredible backdrop from the three decks of super-cruiser Sydney 2000.

But did you know the party going on under the surface of the sparkling Harbour water is just as vibrant as the one above on Sydney Harbour?

Watsons Bay heads with lighthouse Hop On Hop Off sightseeing non-ccc dnsw
Rocky shoreline of Watsons Bay heads

The underwater landscape

Like the diverse topography above the water, the underwater and foreshore landscapes are also intriguing. Within Sydney Harbour, there are rocky shorelines that provide habitat for snails, Sydney rock oysters, limpets, sea squirts, anemones and sea urchins.

There are kelp gardens, sponge gardens, mangrove forests, underwater fields of seagrass and rock shelves where fish feed, hide and breed and crustaceans are found.

Sydney Harbour’s natural underwater landscape has an average depth of 13 metres (42 feet), with deep channels used for shipping of 28 to 55 metres (91to 180 feet) in depth. The shallow areas range from 3 to 5 metres deep (9 to 16 feet).

Open water makes up for ten times the amount of all habitats in the Harbour, transporting nutrients in and out of the Harbour and creating habitat for plankton, small fish and Harbour highways for large fish, sharks and other marine animals.

Family whale watching snapping pictures of humpback whales blowing wildlife non-ccc dnsw
Whale Watching off Sydney

What’s under that sparkling Sydney Harbour water?

Despite being in the centre of a populous modern city, Sydney Harbour supports a broad range of marine life.

The Australian Museum records show that nearly 600 species of fish live in or enter Sydney Harbour, some of which were recorded in times past. As a point of comparison, that’s more than are found in the Mediterranean Sea.

There are all sorts of fascinating inhabitants, like blue dragons (a sea slug with blue finger like appendages and a sting on the end). Have you ever seen a pineapple fish? They really look like a pineapple with their green-gold scales divided by brown borders. Mourning cuttlefish with their quick camouflages and giant sea slugs called sea hares are found in the seagrass beds. The hairy, striped anglerfish likes to sit perfectly still on the seafloor and likes to do so under Sydney’s wharves.

And then there are the whales that feature on the annual whale migration season. Book your Whale Watching tour of Sydney Harbour here.

Pork Jackson shark in Sydney Harbour - stock
Port Jackson shark in Sydney Harbour

Did somebody say shark?

The Port Jackson shark is named after the body of water known as Sydney Harbour. These bottom dwelling, sea grass loving creatures have a blunt head and harness like markings and are not likely to be interested in humans. Bull sharks also frequent Sydney Harbour, and these are more dangerous to people. The bottom feeding dusky whaler (bronze whaler) and carpet like wobbegong also call the Harbour home.

Did you know? The word wobbegong is believed to come from an Australian Aboriginal language.

Is it safe to swim in Sydney Harbour? While shark attacks do occur around Australia and on the NSW coastline from time to time, the last fatal incident in Sydney Harbour occurred in 1963 in Middle Harbour. Most have shark nets.

Little penguin at Manly - stock
Little penguin at Manly

Have you ever seen a little penguin?

A colony of little penguins has its burrows in Manly. Only found in South East Australia (and New Zealand). By day the colony leaves land to spend the day at sea, up to 20km (12.5 mi) off the coast, feeding on small fish, squid and krill. After dark, they return to their burrows.

Fun Fact: The little penguins often play among the summer swimmers in the shallows at Camp Cove on the other side of the Harbour. Likewise, it’s not unusual to see an occasional seal or dolphin frolicking in the harbour, although it is not their natural habitat.

Clifton Gardens Chowder Bay Mosman ferry stop on Hop On Hop Off HOHO
Clifton Gardens Ferry, Chowder Bay

Dive and snorkel spots on Sydney Harbour

Chowder Bay

At Chowder Bay, the dive site at Clifton Gardens is home to an incredible array of marine life. You will always see several species of a sea horse and the site’s signature species; decorator crabs. It’s a great place to snorkel too. Around the jetty and on the sea floor, you are likely to see tiger pipefish, anglerfish and frogfish.

Sydney Harbour’s usual suspects include blue lined goatfish, leatherjackets, goatfish, bottom dwellers such as blennies, threefins and gobies. You can also witness stingarees or octopus. Just 6 kilometres by road from the city (and quicker via Ferry from Circular Quay). How many cities in the world can offer such marine diversity so close to the centre?

Snorkel at Camp Cove

Camp Cove in Sydney’s Eastern suburbs is a small, sheltered beach and gained its name as the place the First Fleet camped on arrival at Port Jackson in 1788. The beach is popular, with just 250m (820 ft) of sand and clean, calm waters flowing from the entrance to Sydney Harbour.

The north end of Camp Cove beach is great for snorkelling. Protected by South Head, sea life is abundant.

Spot seahorse, cuttlefish, sea-dragon, Sydney octopus, goatfish, yellow tail, luderick and schools of damselfish. You are also likely to see hermit crabs, sea anemones and sea urchins here. By the small pier and pumphouse, witness flat head and sting rays on the sand too.

Divers are often found here, too, learning the ropes in group classes. Visit Camp Cove on the Captain Cook Cruises Sydney Harbour Explorer ferry - hop off at Watson’s Bay and walk around to Camp Cove. Easy and pretty!

South Head seal colony

With an open water qualification, scuba divers can join a charter to South Head to dive with Sydney Harbour’s Australian Fur Seal Colony. Found on the ocean side, divers are guided through a boulder field to witness colourful sponges and corals, several species of sharks and resident weedy sea dragons which can be found in the kelp at the reef edge.

There is so much marine life near Australia’s largest city! The natural Harbour with good water flow out to the Tasman Sea offers clean water for swimming and healthy habitats for marine life. Another reason why Sydney Harbour is the most beautiful Harbour in the world.

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