What is a Port Jackson Shark?

A Port Jackson shark is named for its home around Port Jackson, Australia. This nocturnal, bottom-dwelling shark is found exclusively in Australian waters, most commonly along the southern coast. Belonging to a family of sharks with distinctive teeth, the Port Jackson Shark's scientific name is Heterodontus portusjacksoni. In Latin, heterodontus means “different tooth.” Port Jackson Sharks are not considered harmful to humans.

The Port Jackson shark is distinguished by its blunt head and spines on the edge of its two dorsal fins. These spines are common to all eight species of sharks in the heterodontus genus. The spines are also the reason heterodontus sharks are often referred to as “horn sharks.” The fin spines are blunt on adults, but sharp on the young, or pups. Port Jackson sharks are most commonly light brown, and the black harness-like bands found around the shark's upper body are specific to the species.

While some species of sharks produce live young, the Port Jackson shark is oviparous, meaning that it lays eggs. After the autumn mating season, females lay their eggs in rocky areas, frequently close to shore. The eggs change color from olive green to brown in the first few weeks but take 10 to 11 months to mature before hatching.

The female Port Jackson shark matures at a slower rate than the male. The male will grow to maturity after eight to 10 years, but the female does not mature until 11 to 14 years. The female, however, is bigger on average than the male, measuring about 31 inches (78.7 cm), compared to 23 inches (58.4 cm) for the male.

Unlike more famous sharks, Port Jackson sharks have small mouths with back teeth much like molars, and their front teeth are wide and blunt. Their teeth are designed to grind and break the shells of their primary food, sea urchins and crustaceans. These sharks do eat various fish, but only pups chiefly eat soft foods, because they do not yet have all of their adult teeth.

A notable characteristic of Port Jackson sharks is that they can eat and breathe at the same time. Many sharks need to swim in order to manually push water over their gills, which forces them to continue moving in order to breathe. Port Jackson sharks, however, can pump water over their gills using their first gill slit. Thus, they can breathe without having to move and often stay stationary near the bottom of their environment for long periods of time.

The Port Jackson Shark is a distinctive species of bullhead shark native to the coastal regions of southern Australia. Recognizable by its blunt head and harness-like markings, this shark can grow up to 1.65 meters in length. It's a bottom-dweller, feeding primarily on sea urchins, mollusks, crustaceans, and fish.

Identifying a Port Jackson Shark is relatively easy due to its unique features. It has a broad, flat head, prominent crests above its eyes, and a harness-like pattern across its back. The coloration is generally grey or brown with black bands, and its mouth is located underneath the snout, unlike many other sharks.

The Port Jackson Shark is found in the temperate waters of southern Australia, from southern Queensland to Tasmania and west to the central coast of Western Australia. They prefer rocky bottoms, seagrass beds, and sandy areas near reefs, typically at depths of up to 275 meters.

The diet of the Port Jackson Shark consists mainly of hard-shelled mollusks, crustaceans, sea urchins, and fish. They have strong jaws with flat teeth that are adept at crushing the shells of their prey, making them specialized feeders within their marine ecosystem.

Port Jackson Sharks are considered harmless to humans. They are a docile species and are known to be relatively placid when encountered by divers. There have been no recorded incidents of a Port Jackson Shark attacking a human, making them a low-risk shark for those swimming or diving in their habitats.

Port Jackson Sharks have an interesting reproductive method. They are oviparous, meaning they lay eggs. Females produce spiral-shaped eggs that they wedge into rock crevices for protection. These eggs take about 10 to 12 months to hatch, with the young sharks being fully independent from birth.