How do marine animals adapt to hypertonic sea water?

Explanation

To overcome the problem of water loss, marine fishes have aglomerular kidneys with less number of nephrons. Such kidneys minimize the loss of water through urine. To cornpensate water loss the marine fish drink more water and along with this water, salts are added to the body fluids and distrub the internal equilibrium. To maintain salt balance (salt homeostasis) in the body they have salt secreting chloride cells in their gills. Marine birds like sea gulls and penguins eliminate salts in the form of salty fluid that drips through their nostrils. In turtles the ducts of chloride secreting glands open near the eyes. Some cartilaginous fishes retain urea and trimethylamine oxide (TMO) in their blood to keep the body fluids isotonic to the sea water and avoid dehydration of the body due to exosmosis.