Ghost Shark

About

The Australian Ghost Shark is a cartilaginous fish (Chondrichthyes) belonging to the subclass Holocephali (chimaera).

Sharks, rays and skates are the other members of the cartilaginous fish group.

Alternative names include elephant shark, makorepe, whitefish, plough-nosed chimaera, or elephant fish. 

Scientific Name

Callorhinchus milii

Distribution

It is found in southern Australia, including Tasmania, and south of East Cape and Kaipara Harbour in New Zealand. Despite several of its names, it is not a shark, but a member of a closely related group.

Features

The fish is silvery in colour with iridescent reflections and dark, variable markings on the sides.

The size of females is larger than males at maturity and the maximum length head to tail is 1.5 m.

It has an elongated body, which is smooth and torpedo-shaped, with two widely separated, triangular dorsal fins.

They use their hoe-shaped snouts to probe the ocean bottom for invertebrates and small fishes.

This fish has three cone pigments for colour vision (like humans).

They are sometimes referred to as the ocean’s butterflies as they glide through the water with their large pectoral fins.

Reproduction 

From spring to autumn, adults migrate inshore to estuaries and bays and females lay their eggs on sandy or muddy substrates.

Diet

The usual diet of chimaeras consist of crustaceans, and more specifically, they include ophiurans and molluscs.

Conservation status

The IUCN Red list of Endangered Species has kept them in the Least Concern category.

Ghost Sharks

Chimaeras are cartilaginous fish in the order Chimaeriformes , known informally as ghost sharks, rat fish, spookfish, or rabbit fish; the last three names are not to be confused with rat tails, Opisthoproctidae, or Siganidae, respectively.

At one time they were a "diverse and abundant" group (based on the fossil record).

Their closest living relatives are sharks and rays, though their last common ancestor with them lived nearly 400 million years ago.

Threats:

Despite their secluded habits, some chimaera species may be threatened by overfishing through bycatch or commercial exploitation.

Conservation status :

No species are listed as Endangered according to the IUCN, but four are listed as Vulnerable, four more as Near Threatened, and many more as Data Deficient (too rare to evaluate).

All the remaining points including distributions, diet, reproduction, etc are the same as Australian Ghost Sharks.

PRACTICE QUESTION

Q.Consider the following statements about the “Australian Ghost Sharks” recently seen in the news: 

1. They belong to the same cartilaginous fish group as Sharks, rays and skates.
2. They are found in Australia only.
3. They lay their eggs on sandy or muddy substrates.

How many of the above statements is/are correct?

A.Only one

B.Only two

C. All Three

D.None

Answer: B

Explanation:

Statement 1 is correct:

The Australian ghost shark is a cartilaginous fish (Chondrichthyes) belonging to the subclass Holocephali (chimaera). 

Sharks, rays and skates are the other members of the cartilaginous fish group. 

Alternative names include elephant shark, makorepe, whitefish, plough-nosed chimaera, or elephant fish.

Statement 2 is incorrect: 

It is found off southern Australia, including Tasmania, and south of East Cape and Kaipara Harbour in New Zealand, at depths of 0–200 m (0–656 ft). Despite several of its names, it is not a shark, but a member of a closely related group.

Statement 3 is correct: 

From spring to autumn, adults migrate inshore to estuaries and bays and females lay their eggs on sandy or muddy substrates.