What is the function of the rectal gland on a shark?

Answer 1

The rectal gland of a shark secretes salt in order to help maintain osmotic balance with the seawater. It is found in the posterior end of the shark and resembles a small, pink rolled tube.

Source(s):

College level Biology Student

Answer 2

The rectal gland of the spiny dogfish, Squalus acanthias, secretes a fluid which is essentially a sodium chloride solution with a concentration about twice that of the plasma and greater than that of sea water. Observed volumes of flow are sufficiently large to make it clear that the rectal gland can remove from the blood relatively large amounts of sodium chloride, and presumably this is its function.

1 Trinity College, Hartford, Connecticut, and Mount Desert Island Biological Laboratory, Salisbury Cove, Maine
2 Hamilton College, Clinton, New York, and Mount Desert Island Biological Laboratory

Answer 3

Secretes salt to help the shark maintain osmotic balance with the seawater