Atlantic Cod is a marine fish. The fish has less salt in its internal body while the salt concentration in the sea water in which the Cod lives is high. Thus through the process of osmosis ( a process in which an element moves across a permeable membrane from regions of high concentration to the regions of low concentration) the salt moves from the ocean into the fish body. In such scenario the metabolism of the fish body gets disturbed, and there is an urgent need to remove the excess salt with the help of Kidney (through extremely concentrated urine) by going against the concentration gradient in order to maintain the homeostasis.
Answer:
The Atlantic cod is fish of Atlantic ocean that continuously drinks water to fulfill its needs, however, this fish is not an ocean osmoconformer. The concentration of the salt is less than the seawater in the fish. It removes water by the process of osmosis which is active transport to the ocean.
The homeostasis is maintained by these fishes by removing excessive salt from the body and as it moves against the gradient that is active transport, this process requires energy. These fishes excrete urine in a very concentrated form.
