What is Sydney's Most Common Shark?

The Port Jackson Shark is the common shark seen by divers in the waters around Sydney. Port Jackson Sharks are considered non-threatening to humans. Their teeth are not sharp, yet they can give a painful bruising bite. If provoked, they have also been known to bite and expend considerable energy attaching themselves to the diver, leaving a visible hickey-like bruise.

This medium-sized Australian shark has a blunt head with a small mouth and prominent crests above its eyes. It is usually a light grey brown with black bands across its eyes and keels across its back that run diagonally. It is lovingly known as a PJ to Sydney divers.

The breeding season for the Port Jackson shark typically takes place during late winter and early spring. During this time, they are most prevalent around Sydney and divers often observe the sharks gathering in caves, under ledges, and in gutters, particularly during the winter months.

Female Port Jackson sharks lay eggs. The egg case is a tough, chestnut brown spiral about 7 cm to 8 cm wide and 15 cm long. It is common for them to be found washed up on beaches. Females can lay up to sixteen eggs during each breeding season. An embryo develops for 10-11 months before hatching from its egg capsule completely.

According to a tagging study that Abyss was involved with in 2000, Sydney sharks migrate vast distances each year (600-800 kilometres) between their feeding grounds in Bass Strait and reproductive aggregations along the New South Wales coast.

PJ’s sharks can grow up to 1.65 meters and can live for 30 years. Female Port Jackson sharks mature at 11 to 14 years of age, with males maturing at 8 to 10 years.

PJ’S forage for food at night when their prey is most active. They eat molluscs, crustaceans, sea urchins, and small fish. They often use caves and rocky outcrops as protection during the day, although if you examine the sand to the east of Bare Island during September to October, you will discover them laying there by the hundreds.

Where Can You Dive with Port Jackson Shark in Sydney?

Port Jacksons can be found at various dive sites around Sydney from July to September. However, if you are interested in seeing large groups of these sharks, I would suggest going to Cape Solander, the western side of Bare Island, and Fish Soup at Oak Park.

If you are interested in observing a baby Port Jackson shark, they are often located at Bass & Flinders and Oak Park during January and February. During those months, we do organize special dives to observe the Port Jackson sharks.

Types of Sharks in Sydney Harbour

The Big Three sharks, the great white, bull sharks, and tiger sharks are rarely seen in Sydney Harbour. However, there are over 30 shark species in the waters around Sydney; besides seeing the Port Jackson shark, you're likely to come across its close relative, the crested horn shark; grey nurse sharks; wobbegongs; hammerhead sharks; bronze whalers; makos; and Dusky Whaler sharks.

How many sharks are in Sydney harbour?

Sydney Harbour is one of the largest natural harbours in the world, covering an area of approximately 55 square kilometres with a shoreline of over 240 kilometres. Despite its size, Sydney harbour is home to only around 180 species of sharks, with the most commonly seen species being Port Jackson Sharks, Wobbegongs, Grey Nurse Sharks and Bull Sharks.

The majority of these sharks inhabit the deeper waters of Sydney harbour. However, some species such as Grey Nurse Sharks can occasionally be seen closer to shore. It is estimated that there are between 15,000 and 20,000 sharks living in Sydney Harbour at any given time, with a maximum of around 100 individuals per species although in the breeding season, there are very many more Port Jackson sharks.

Despite its large size and population of sharks, it is generally safe to swim in Sydney Harbour. Shark encounters are extremely rare due to the fact that they tend to inhabit deeper waters and avoid areas where humans frequent.

Overall, while there may be a significant number of sharks living in Sydney Harbour at any given time, it is generally safe for humans to swim in its waters due to their tendency to stay away from populated areas.

SCUBA DIVING WITH SHARKS

Interesting Facts About the Sydney Harbour Shark Population

1. There are over 30 species of sharks that call Sydney Harbour home. The main species are Port Jackson Sharks, Bull Sharks and Wobbegong Sharks.

2. There has been a total of 29 confirmed shark attacks in Sydney Harbour since 1791, or approximately one every eight years.

3. Sharks have been swimming in Sydney harbour for over 400 million years!

4. The oldest shark fossil ever found was discovered in Australia and is estimated to be around 400 million years old.

5. Sharks are essential to the health of our oceans and play a key role in the food chain.

6. Sharks are often misunderstood and feared by humans, but they are actually very shy creatures that pose little threat to us.

7. There have only been two fatal shark attacks in Sydney Harbour in the past 100 years.  The two species of sharks involved were bull sharks and tiger sharks.

8. Shark populations around the world are declining due to overfishing, habitat loss, and pollution.

9. We can help protect sharks by supporting sustainable fishing practices, conserving their habitats, and reducing our plastic consumption.

10.  Bull sharks are one of the few species of sharks that can live in both salt and fresh water.

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