Saturday, January 26, 2013

Elephant Shark

Callorhinchus milii
The Elephant Shark goes by many, many names. Ghost Shark, Whitefish, Elephant Fish, and Silver Trumpeter are all names given to Callorhinchus milii, a cartilaginous fish that is a member of the Chimaera subclass. Despite the name they are not Sharks. Sharks, Skates, and Rays are their distant cousins, and they share an overall Class.

Elephant Sharks cane be found in the continental shelf waters off of Australia and New Zealand. They don't tend to go much deeper than 200m, and they actually move very close to shore for reproductive purposes. They lay egg cases in the substrate of shallow water, and when the eggs hatch after 8 months, the young Sharks  will live  in the shallow areas until they grow larger.

Now, you may be wondering what they weird nose-thing is. That protrusion is actually covered in sensory pores that the Elephant Sharks use to locate food. They can detect the small movements and electrical fields that come from the shellfish and mollusks that they eat.

Elephant Sharks have been commercially and recreationally fished in Australia and New Zealand for a number of years. The population is stable, and the species is listed as being of Least Concern.

One final fact about the Elephant Shark is that its genome is currently being sequenced. It has the smallest genome of any of the cartilaginous fishes, which makes it an ideal candidate. Cartilaginous fishes are some of the oldest jawed vertebrates, so understanding their genome gives us a better look at vertebrate evolution.

IUCN Status : Least Concern
Location : Australia and New Zealand
Size : Length up to 47in (1.2m)
Classification : Phylum : Chordata -- Class : Chondrichthyes -- Order : Chimaeriformes
Family : Callorhinchidae -- Genus : Callorhinchus -- Species : C. milii

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