Port Jackson Shark

• Maximum length1.65 m (5.4 ft); most adults 75–100 cm
• WeightNo reliable published maximum; a large female is roughly 10 kg (22 lb)
• LifespanProbably 25–30 years (not validated)
• Depth rangeIntertidal to 275 m (900 ft), mostly under 100 m
• DietSea urchins, molluscs, crabs, worms, small fish
• IUCN statusLeast Concern (assessed 2015)

How to recognise a Port Jackson shark

Few sharks are as easy to name underwater. The head is the giveaway: a short, blunt snout, a small mouth set well under it, and a thick ridge of skin above each eye that gives the animal a frowning, bulldog expression. Behind the head the body is stout and tapers to a tail whose upper lobe is much the longer of the two. Both dorsal fins carry a stout spine on their leading edge, a family trait shared with the horn shark of California and the crested bullhead that lives alongside it. The spines are not venomous; the old claim that they are has no support in the literature.

Colour settles any doubt. The base is pale grey to light brown, and over it runs a bold dark pattern that divers call the harness: a band across the head that drops through each eye, a stripe along the back to the first dorsal fin, and a pair of lines that cross the flanks behind the pectoral fins. No other Australian shark wears it. The crested bullhead, the only species you could confuse with it, has broad dark saddles instead of a harness and much taller eye crests.

Open the mouth and you find the feature the genus is named for: Heterodontus means different teeth. The front teeth are small, sharp cusps for gripping; the back teeth are broad, flat and rounded, a crushing plate that would look more at home in a ray. It is the toolkit of a shark that eats shells, which is why fishers once called it the oyster crusher.

How big do Port Jackson sharks get?

The Port Jackson shark is the largest of the bullheads, but that is a modest title. The biggest reliable measurement is about 1.65 m (5.4 ft) total length, and animals over 1.4 m are uncommon. What divers meet on the reefs of New South Wales are typically 75 to 100 cm: males settle at around 75 cm and females, which grow larger and mature later, at 90 cm to a little over 1 m. Weight is rarely recorded because the species has no commercial value; a large female is in the region of 10 kg (22 lb), and no reliable maximum has been published.

Hatchlings leave the egg case at about 23 to 25 cm (9 to 10 in) and grow slowly. Males reach maturity at roughly 8 to 10 years, females at 11 to 14, and growth almost stops after that, so a 1.2 m female is a genuinely old animal. Sexual dimorphism is easy to see in adults: apart from the size difference, males carry a pair of claspers behind the pelvic fins and their harness markings tend to fade with age.

The size bar below compares the largest recorded Port Jackson shark with a 1.8 m diver. Put a typical adult next to the same diver and it reaches about the knee.

Where Port Jackson sharks live

This is a cool-water shark, not a tropical one. It is endemic to southern Australia, from about Byron Bay and Moreton Bay in southern Queensland, down the whole New South Wales coast, through Victoria, Bass Strait and Tasmania, across South Australia and up the west coast to Geraldton and the Houtman Abrolhos in Western Australia. A few strays have been recorded in New Zealand, but it does not breed there. Genetic work suggests the eastern and southern-western animals form two largely separate populations.

Its depth range runs from rock pools and shallow bays to 275 m (900 ft) on the outer shelf, but most of its life is spent in far less than 100 m. The figure of 100 to 275 m that circulates online describes the offshore end of the range, not where you would look for one. By day it lies up in caves, under ledges and in gutters on rocky reef, often in groups of a dozen or more; at night it moves out over sand, seagrass and kelp to feed. Water temperatures across the range run from about 12 to 22 °C.

The best-known aggregation sites are the reefs of Sydney Harbour, Jervis Bay and Port Stephens in New South Wales, where hundreds gather each winter.

What Port Jackson sharks eat

The menu is written in the teeth. Sea urchins make up the largest part of the adult diet along the New South Wales coast, followed by gastropod and bivalve molluscs, crabs, prawns, polychaete worms and the occasional small bony fish. Everything on that list is slow, armoured or buried, so the hunt is a patient search over the bottom at night rather than a chase. The shark noses along the sand and reef, finds prey by smell and by the electroreceptive pores on its snout, and uses its small, protrusible mouth to suck the animal in.

Once inside, a spiny urchin or a whelk is passed back to the molariform teeth and crushed. A Port Jackson shark generates a surprisingly high bite force for its size, and its jaw joint is built to take the load; captive animals crack mussels and split urchin tests with an audible pop. Juveniles, whose back teeth are still relatively pointed, eat a softer diet of worms and small crustaceans, and they have a trick of gulping a mouthful of sand, blowing it out through the gill slits and swallowing whatever edible remains.

Feeding and breathing are separate jobs for this shark. Because it can pump water over the gills, it does not need to swim to breathe and can chew a hard meal while lying still. Our page on how sharks breathe explains why that matters for a species that spends the whole day motionless in a cave.

Behaviour, senses and social life

The Port Jackson shark is one of the most studied sharks in the world for the simple reason that it is common, hardy and easy to catch, and much of what we know about shark learning and personality comes from it. Experiments at Macquarie University in Sydney have shown that individuals differ consistently in boldness, that they can be trained to associate a sound cue with food, and that they learn faster when they watch a trained companion. They also recognise and prefer particular reef-mates: on a winter reef the same sharks rest together night after night, and the groups are not random.

Its senses are those of a bottom hunter. Smell works over tens of metres down-current, not the miles of legend; the ampullae of Lorenzini on the snout find the faint electric fields of buried worms and clams; and the small eyes cope well with dim light. A spiracle behind each eye lets it draw water in while the mouth is buried in sand.

The most remarkable behaviour is the annual migration. After breeding on the reefs around Sydney in late winter both sexes leave, males first, and tagged sharks have travelled up to 850 km (530 mi) south to Bass Strait and Tasmania before returning to exactly the same breeding reef the following winter. The sexes spend most of the year apart in different habitats before meeting again in July.

Reproduction, egg cases and lifespan

The Port Jackson shark is oviparous, and its egg case is the most distinctive of any shark: a dark brown, corkscrew-shaped capsule 7 to 8 cm across and about 15 cm long, with two broad spiral flanges winding around it. Mating takes place on inshore reefs in July and August, and the females lay in August and September, usually in pairs every eight to seventeen days until 10 to 16 have been produced. A fresh case is soft; the mother picks it up in her mouth and screws it into a rock crevice, where it hardens within days and cannot be pulled out by a predator. Most are laid in 1 to 5 m of water, some as deep as 30 m, and females return to the same crevices year after year.

Development is slow. The single embryo takes 10 to 12 months to use up its yolk, and the pup that backs out of the case is 23 to 25 cm long and a perfect miniature of its parents. Empty cases are a common find on beaches from Sydney to Adelaide. Young sharks stay in shallow bays and estuaries for several years before joining the adult migration.

Maturity comes late for such a small fish: 8 to 10 years for males and 11 to 14 for females, at roughly 50 to 70 cm and 80 to 95 cm respectively. Lifespan has not been validated by any ageing study; growth-based estimates run to 25 or 30 years. Our guide to how long sharks live explains why such late-maturing species are sensitive to fishing even when abundant.

Are Port Jackson sharks dangerous?

No. The SharkSider database contains exactly one incident attributed to this species, a small bruise to the calf of a diver at Elwood Beach, Victoria, in October 2011, from a shark of about a metre. That is the entire record, with no fatalities and nothing else in more than a century of Australian reporting. A mouth built for crushing urchins, set underneath a blunt head, is simply not capable of inflicting the kind of wound that the Australian attack record associates with white, tiger and bull sharks.

The two ways to get hurt by a Port Jackson shark both involve picking one up. A handled shark may twist round and clamp onto a hand, and the grip is strong and hard to break; and the dorsal spines, which are needle-sharp in juveniles, will puncture a palm or a wetsuit. Anglers who catch them on bait should unhook them in the water. Left alone on the reef they ignore divers completely, which is why they are the first shark most Australians ever swim with.

Port Jackson Shark incidents in the SharkSider database

• Records attributed1
• Fatal0 (0%)
• Years covered2011–2011
• Since 20001 incidents, 0 fatal
• Most common activityDiving & spearfishing
• Most recordsAustralia (1)

The six most recent records attributed to the port jackson shark

• 19 October 2011 · Elwood Beach, Victoria, AustraliaDiving — Small bruise to calfRecorded as: Port Jackson shark, 1m · not fatal

Records are matched on the shark named in each report (“port jackson”), so they include incidents where the species was reported rather than confirmed. Full records by country on the shark attacks pages.

Conservation status

The IUCN Red List assesses the Port Jackson shark as Least Concern (2015), with a stable population trend. It is among the most abundant sharks on the southern Australian shelf and shows no sign of decline. It is not listed under CITES or the Convention on Migratory Species, and there is no targeted fishery, because the flesh is considered poor eating and the fins have no market.

That does not mean it is untouched. It is one of the most frequently caught species in the demersal gillnet and trawl fisheries of southern Australia, above all the gillnet fishery for gummy sharks in Bass Strait, where it is sometimes the most numerous animal in the net. Almost all are discarded, and because the species is tough, most survive if released promptly. Some anglers kill them as a bait-stealing nuisance. Catch records lump this species with the crested bullhead, so the true bycatch figure is unknown.

Marine parks protect a share of its breeding reefs, Western Australia sets a recreational bag limit, and aquarium collectors need a licence; beyond that there is no species-specific management, and none is currently thought necessary. Its hardiness makes it a staple of public aquaria, which have bred it for decades. Its relatives on our list of threatened sharks are in a very different position.

Similar species and close relatives

The bullhead sharks are an ancient and compact family, nine species in a single genus, and the Port Jackson shark is the biggest of them. Three live in Australian waters. The crested bullhead shares the reefs of New South Wales and southern Queensland and becomes the commoner of the two as you go north; it is smaller, browner, banded rather than harnessed, and carries very tall crests over the eyes. The zebra bullhead of the north-west shelf is striped in black and white. Further afield are the spotted horn shark of California, the Japanese bullhead, the Galápagos bullhead of Peru and Ecuador, the whitespotted bullhead of the Indo-Pacific and the little-known Oman bullhead. All share the blunt head, spined dorsal fins, crushing dentition and spiral egg case, a body plan barely changed since the Jurassic (see the evolution of sharks).

Outside the family, nothing in Australia looks much like it. A draughtsboard shark or a wobbegong may share the same cave, but the first has no dorsal spines and the second has a flattened head fringed with skin lobes.

• Crested Bullhead Sharkspecies profile
• Zebra Bullhead Shark (Heterodontus Zebra)species profile
• The Horn Sharkspecies profile
• Japanese Bullhead Sharkspecies profile
• Galapagos Bullhead Sharkspecies profile
• Whitespotted Bullhead Sharkspecies profile

Written and reviewed by

SharkSider Editorial Team

A small team focused on researching sharks and making marine biology easy to understand. Every page is reviewed against current species records and the SharkSider attack database, and updated when new incidents or research appear.

Published December 1, 2014 · Last updated September 22, 2026 · 1 incident attributed to the port jackson shark in the SharkSider attack database (0 fatal), updated weekly.