Common Name: Prickly Dogfish

Scientific Name: Oxynotus bruniensis

 

Kingdom: Animalia

Phylum: Chordata

Class: Chondrichthyes

Order: Squaliformes

Family: Oxynotidae

Genus: Oxynotus

Species: O. bruniensis

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The Prickly dogfish are one of the strangest types of sharks that you may ever see. Male dogfish can be up to 60 cm (5 ft) long and females up to 67 cm. They have a uniform, dark brown color and their skin is very rough like sandpaper. They have a short nose, spear-shaped teeth in the upper jaw and blade-like teeth in their lower jaw. Their mouth is used to suck up the waste along the bottom of the ocean. Not much is known about the dogfish but scientist and marine biologist believe the dogfish were adapted from whale sharks because of its shape. It is recognized by its humpback body and flat bottom. It has two dorsal fins and does not have an anal fin. Fish that live near the bottom of the have this shape because it uses less energy.

 

The Prickly Dogfish are found in the cold waters of New Zealand and Australia. Their habitat is 300 to 600 meters deep in water 31 to 55 degrees. They do well in this ecosystem because they are none aggressive and by staying in deep waters they are able to stay away from many ocean predators. There is not a lot known about the population of the prickly dogfish. They are ovoviviparous, which means they give birth to well developed young. The females give birth to 7 or 8 young but their birth rate is low and scientists believe only half of the young survive. This keeps the population low because it takes more than 14 years to double the population. The prickly dogfish are not seen very often and are not caught by commercial fishermen because of the depth they live in. There are no conservation actions in place at this time and they are not on the endangered species list.

 

The diet of the Prickly Dogfish consists of benthic invertebrates such as segmented worms. They also feed on small fish. Because they live so deep in the water there is not much to eat and there is not much fish to compete for food. The Prickly Dogfish does not have any known predators. Because it lies so flat to the ground and blends in with the sand of the ocean they aren't seen by other cold water predators such as larger sharks and fish. What stood out to me is that it might be a prehistoric creature and it has stayed alive all of these years? I was also surprised at how ugly they are! I learned that there are many things in the ocean that haven't been discovered or studied by a scientist. The picture on my title page is was a prickly dogfish that washed up from the Indian Ocean after the tsunami in 1984. There are other interesting pictures on the website of other ocean creatures that washed up after the tsunami.

 

Author: Aaron F

Publish: 05/2009

 

Sources: Sharks & Rays Tricas, Timothy C., Deacon, Kevin, Last, Peter 1997 Time Life Books Inc. Prickly dogfish Wikipedia http://en.wikipedia.org/Oxynotus bruniensis Prickly dogfish Australian Museum Online 2006 www.amonline.net.au/fishes Oxynotus Bruniensis The IUCN Red List of Threatened Species 2008 www.iucnredlist.org Prickly Shark Picture Yale Peabody Museum 2005 http://www.advancedaquarist.com/images/feb2005