The World Ocean is under threat, because it is polluted a lot. People get oil and some of it usually goes into water. There have recently been several catastrophes, when a lot of oil spread all over some seas and oceanic coastlines. Plants and factories drop poisonous chemicals, litter and waste into the water and make it impossible to live in. Because of such events many birds and animals die, a lot of plankton disappears. It also brings less oxygen to water and all animals and fishes can die out. Big oceans are poisoned only in some places, but small seas are really in danger.
Fishing.
Fishing is another catastrophe. Scientific and technological progress resulted in using by people many devices. Modern ships have special equipment to catch even the whole school of fish. That is why herring and cod are almost caught out. While catching shellfish people damage the bottom. As a result many animals die.
