21 Apr 2016

Port Jackson Shark Facts, Images and Other Info


port jackson shark

 

Interesting Facts About Port Jackson Shark [Heterodontus portusjacksoni]

 

Do you find the name “Port Jackson Shark” funny? Well, the owner of the name looks funnier. This species of shark belong to the “bullhead shark” family. Bullhead sharks (Heterodontiformes) are also known as Horn sharks (a bull has a pair of horns, right?).


So, that shark has a nice bull like head with two horns. Well, the shark does not actually look like a bull, but we know there is some resemblance. The horn like things above its eyes is in reality nothing but crests.


The name Port Jackson came from the natural harbor of Sydney. It is the location of first European settlement in Australia. The shark can often be found near the port.



Port Jackson Shark Quick Facts 

 

Port Jackson Shark Facts

Family: Heterodontiformes
Scientific Name: Heterodontus portusjacksoni
Habitat: Coastal waters of Australia
Size: 1.67 m (5.5 ft)

Habitat and Range of the Port Jackson Shark


From the above list you know that the shark lives in the ocean near the shores of Australia. They are most common in the seas of southern Australia and Tasmania. The western coast is also worthy to be mentioned. We can found one or two specimens near New Zealand, too.


 Port Jackson Shark is a bottom dweller. Like most bottom dweller fishes they prefer sea bottoms with plenty of places for hiding. So, they live in the rocky underwater environments. Sea beds with kelp forests is their another favorite. It is natural because every predator loves forests.


Port Jackson Shark in a Kelp Forest
Port Jackson Sharks love kelp forests

330 ft or 100 m is their preferred depth, but it is not uncommon for some to live in the seabed below 300 m (990ft) of water. In such depths, the sunlight becomes very weak.



Physical Features

 

Port Jackson Shark Anatomy lebelled

The newborn baby of the shark species can be 20 to 25 inches long (7.8 – 10 inches). When they mature becomes close to 3 times longer. The females are bigger than the males. The males average between 80 to 90 cm and the females 100 to 110. But the largest can grow up to 167 cm (5.5 ft). Above 130 cm size is not that uncommon among the females.


Everyone will notice at the head of the shark because it is unusual. There is not any snake like angular face of a common shark. Here you will find a broad and flat head. As stated earlier, there are also two crests or “horns” just above the head. Those horns give it a bovine look.


Another important peculiar feature of a Port Jackson Shark is its pair of spiny dorsal fins. Dorsal fins mean the fins on the back. Unlike most of their cousins, the Port Jackson Shark’s back fins are almost equal in size.


The spines are too hard. Sometimes the shark can hit its captors with these spines. Some people believe that the spines have venom but there is not any scientific proof of that. The sharpness of the spines is reduced with age.


They have an unusual looking mouth, too. The nostrils are connected with the mouth and the “horns” over head give it a bizarre look. 


They have a grey and brown colored body. There are black bandings over the back and the sides. There are also thin dark stripes near the back fins.


The teeth of the species are also different. The front row of the teeth is sharp and pointed. Other teeth are blunt and flat. The frontal teeth are for holding, piercing and cutting the prey. The flat teeth are used to crush the hard shells of the mollusks, their favorite food.



What does a Port Jackson Shark Eat?


Heterodontus portusjacksoni mouth
Mouth of the Shark

The Port Jackson sharks are bottom dwellers. So, they generally feed on other creatures that live there. They are night feeders. They feed on sea urchins, mollusks, small fishes, and crustaceans (crabs, shrimps, lobsters). Port Jackson shark eating larger preys than that is rare.


They have a peculiar feeding habit. After sensing the hidden prey electrical field, they often suck the sand with their mouth. Then they filter the prey out and blow out the sand from their gill slits.

Unlike other sharks they can both eat food and take a breath at the same time. Like other sharks they also need not to move to breath. They can pump water through their gills.
 

Reproduction

 

Port Jackson Shark Egg
Egg

The male Port Jackson sharks become sexually active earlier than the females. They need to be 8 to 10 years to be that mature. The females take 12 to 15 years to be sexually mature.
The mating happens once in a year. The season is the Australian winter (July to August). The sharks gather in the reef areas for mating.


They are oviparous in nature that means they lay eggs. The breeding period is August to November. Each year a particular female comes to specific area to lay eggs. He females lay near the site for months laying a pair of eggs each time after 10 to 14 days for 7/8 times. Generally the breeding places are very far away (600 – 800 km) from their feeding grounds.


The females keep the eggs hidden in the caves and crevices. After that they go away from the place. It takes 10 to 11 months for the embryo to be matured. After that it breaks away from the egg. The broken egg shells often come ashore. Local people call them “mermaid’s purses”.



Relationship with Humans


Port Jackson Sharks avoid humans. They are bottom dwellers and so do not come into contact with us. They are considered harmless. But if you try to catch one by hand, expect a sharp bite from those sharp teeth.


These sharks are not caught as food or for their skin. So, they are quiet safe from the hand of humans. But they often get caught as a by catch. Environmental degradation is also harming their normal habitats and food sources.


Port Jackson sharks are not protected  by any conservation law. They are not a threatened species and so they are not going to be extincted soon.


More Information



  • Here is some more information about the Port Jackson Shark congregated at one place.
  • Sometimes these sharks form large groups. These groups can be of mixed sex or of separate sexes.
  • The meaning of the term “Heterodontus” of its scientific name is different (“hetero”) teeth (“dentus”).
  • Juvenile Port Jackson sharks are often kept in aquariums. They can thrive in captivity.
  • They often live in the same area with Crested Bullhead sharks. These species is their cousin.
  • The color pattern of their body helps them to be hidden in dark crevices. But sometimes these sharks are being haunted by other larger sharks or sea lions.
  • The male sharks have a very nasty habit of eating the eggs.


Port Jackson Shark Images


Here are some more images of Port Jackson Shark for you.

With an Egg
With an Egg

Couple of sharks
A Couple

Heterodontus portusjacksoni
Waiting for Prey

Group of H. portusjacksoni
A Group of Port Jackson Shark Babies

Hidden shark
Hidden in a bush to ambush



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