Port Jackson shark

Appearance

Port Jackson sharks are similar to other organisms in their genus, bearing a broad, flat head, an anal fin, and crests above its eyes.

However, the species possesses characteristics that make them easily identifiable—their teeth and the harness-like markings which run for a majority of their body length. This feature runs from their eyes to their first dorsal fin and then across the rest of their body. Both of its dorsal fins are of close to equal size, each with a spine at the foremost edge. This is rumored to be of poisonous nature. Other features that help distinguish them are their small mouths and their nostrils, which are connected to their mouth.

The sharks have gray-brown bodies covered by black banding, which covers a large portion of their sides and back. One of these band winds over the face and progresses even to the shark's eyes. Another, harness shaped band goes around the back, continuing until the pectoral fins and sides. Thin dark stripes are also present on the back of Port Jackson sharks. These progress from the caudal fin to the first dorsal fin.

Distribution

The Port Jackson shark is endemic to the waters around Australia—it can be found in southern Australian waters and west of the south central coast of the continent. It is believed to have originated somewhere off the coast of South Africa. On one occasion it has occurred off the coast of New Zealand, however it is usually limited into two groups found from Northeastern Victoria to Western Australia and from Southern Queensland to New South Wales. It usually lives less than 100 metres underwater, but has been known to go as deep as 275 metres.

Status

Although listed as "Least Concern" on the World Conservation Union Red List, it is known that the shark's embryos experience very high mortality rates. Its status is otherwise, largely unknown. Predators of the species are also unknown. Though Crested bullhead shark are known to prey upon Jackson shark embryos, the biggest threat is probably from other sharks such as white sharks and the broadnose sevengill shark.

Habitat

The shark's territory is habitually sited in stone settings on the bottom where it feeds. Though rocky environments are the most common sandy and muddy ones are also possibly, probably near seagrass. Since the shark is nocturnal, during the day it resides in low resistance areas such as caves.

Reproduction

Male Port Jackson sharks become sexually mature between ages 8 and 10, and females at 11 through 14. They are oviparous meaning that their eggs, which are laid annually, are produced in a group, rather than in live birth. Their breeding season begins in August, continuing until the middle of November while the female lays egg pairs off and on for every 10 to 14 days. As many as 8 pairs of offspring can be laid during this period. The eggs mature for 10–11 months before hatching at once from the sac. The babies, known as neonates, have an 89% mortality rate of dying before even being born.