Port Jackson Shark

Port Jackson sharks can grow up to 1.65 metres (5.5 ft) long and are similar to others of their genus, bearing a broad, blunt, flat head, an anal fin, and crests above its eyes. However, the species possesses characteristics that make them easily identifiable, such as their teeth and the harness-like markings which run for a majority of their body length. These markings run from their eyes to their first dorsal fin and then across the rest of their bodies. Both dorsal fins are close to equal size, each with a spine at the foremost edge. These spines are rumored to be venomous. Other features that help distinguish them are their small mouths as well as their nostrils, which are connected to their mouths.

The Port Jackson shark is endemic to the temperate waters around southern Australia and can be found in an area stretching from southern Queensland, south to Tasmania, and west to the central coast of Western Australia. Dubious reports exist of catchings as far north as Western Australia's York Sound. A single specimen of this species was collected in a set net at Mākara, Wellington in 1954. Two more specimens reported as being from New Zealand were presented to the British Museum however although these two specimens have been located they have no information on their collection location to confirm this assertion. and on one occasion, it has occurred off the coast of New Zealand. Genetic studies suggest two Australian groups, one found from Northeastern Victoria to Western Australia and the second found from Southern Queensland to New South Wales.

Port Jackson shark adults are often seen resting in caves in groups, and prefer to associate with specific sharks based on sex and size. Juvenile Port Jackson sharks, on the other hand, do not appear to be social. A captive study showed that these juveniles did not prefer to spend time next to other sharks, even when they were familiar with each other (i.e., tank mates). Juvenile Port Jackson sharks have unique personality traits, just like humans. Some were bolder than others when exploring a novel environment and they also reacted differently to a stressful situation (in choosing a freeze or flight response).

Juvenile Port Jackson sharks are also capable of learning to associate bubbles, LED lights, or sounds with receiving a food reward, can distinguish different quantities (i.e., count), and can learn by watching what other sharks are doing.

Male Port Jackson sharks become sexually mature between 8 and 10 years of age, and females at 11 to 14 years. They are oviparous, meaning that they lay eggs rather than give live birth to their young. The species has an annual breeding cycle which begins in late August and continues until the middle of November. During this time, the female lays pairs of eggs every 8–17 days. As many as eight pairs can be laid during this period. The eggs mature for 10–11 months before the hatchlings, known as neonates, can break out of the egg capsule. The eggs have been assessed in recent studies as having an 89.1% mortality rate, mostly from predation.

The shark has no major importance to humans. It is not an endangered species and is not used as a common food supply. It is, however, useful when scientists are hoping to study bottom-dwelling sharks and can be vulnerable to being caught as bycatch. It also does not pose any danger to humans. In October 2011 a man was bitten by a Port Jackson shark at Elwood Beach near Melbourne. The bite did not pierce the skin and the man was able to swim away while the shark was latched on to his calf.