24 Feb 2016

Dogfish! A Shark with Venom!

Spiney Dogfish Shark
Photo Credit: NOAA (Public Domain)
Dogfish is the common name of a group of similar shark species.The scientists is not fond of such mundane names and so they call them Squaliform. The group is large with 119 members. They have diverse sizes and shapes. All of them do not even have same physical characteristics, too.

The smallest Dogfish species is Dwarf lanternshark (Etmopterus perryi) which never grows beyond 7 /8 inches. Actually, they are the smallest of all sharks. That tiny shark is rare and is endemic to the continental slopes of Venezuela and Colombia. They might be small but they can also impress you by producing light from their body.

The Spiny Dogfish (Squalus acanthias) is the most well known member of the family. It is called “Spiny” because of having two spines near its two spinal fins. The fish has no anal fin. The Spiny Dogfish possess mild venom in its spines. It attacks with its spines. The females are bigger in size and live longer than the males of these shark species. Some of the females can last as long as 21 years.

Mandarine Dogfish is another rare species which can be found undersea near the coast of Japan, Taiwan, and Indonesia. The shark has a similar species roams the seas of Australia and New Zealand.
We can further group the Squliform sharks in 7 groups:
  • Gulper sharks: These medium sized (3 to 5 ft) sharks lives in deep seas. Some of its species are bottom dellers and some roams near the surface.Their most common foods are Octopus, Squids and Shrimps.
  • Lantern sharks: We have known about the smallest Dwarf lantern shark before. All of them have the ability to produce light from their bodies. None of them cross the 3 ft mark in length.
  • Kitefin sharks: Some of the Kitefins can also have bioluminescent capabilities like the Lantern Fish. These sharks can be as long as 6.6 ft. Their snouts are round shaped.
  • Bramble sharks: The Bramble sharks are bigger than most of the Dogfishes. The adults can be anywhere between 10 to 13 ft. their body is covered with thorn like dermal denticles.
  •  Rough sharks: The Rough sharks looks peculiar due to the big dual dorsal fins and triangular shaped body from the bottom. Their skin is also very rough and prickly. They can also produce light. Their size is small (less than 5 ft).
  • Sleeper sharks: They are sleepers but they have huge bodies. They can often be seen near the Arctic regions. Their size can be as big as 24 ft with a weight over 3000 lb. Their meet is toxic.
  • True Dogfish Sharks: We have known about them before.

Common Characteristics of Dogfish Sharks

Photo Credit: NOAA (Public Domain)
Some of the common characteristics of the Dogfish sharks which are present in most species are –
  • No Anal Fin.
  • Sharp, strong fin spines. They have two large spinal fins.
  • Toxicity – the fin spine can have venom or the meet can be toxic.
  • Number of Gill Slits is five.
  • Some of them can produce light.
  • They are all Ovoviviparous i.e. their eggs are hatched inside the mother’s body.
  • They have very rough skins.
  • Most of the species of the Dogfish are bottom dwellers but some lives in open seas. They have diverse habitats from the Subtropical to the Sub-Antarctic.
  • Their favorite food is crustaceans like the Shrimps and Squids.

It our duty as a learned citizen of the world to protect the diversity of the life of this planet. We must make people and government aware about saving the marine animals and its environment. If you like to know more about sharks then you can check this inforgrpahic about Whale Shark.