Answer:
increase.
Explanation:
The pressure inside the deep sea is higher than the air. Because water can't compress like air, and deep down the earth the pressure is more. Therefore, there is more pressure in the deep sea. That's why the lungs and blood vessels of human beings get compressed under water. But fishes have a swim bladder that releases air when it enters into deep water. The body pressure increases maintain equal pressure with water as no air-filled space is present in the fish body. Some marine fishes have an oil-filled bladder. This way fish can adapt to the deep sea pressure.
