As more and more sharks are being hunted, mainly for their fins, the number of top preditors in the ocean is beginning to decline. This may not seem like a bad thing at first as it means that the lower down preditors, the prey of these big sharks, can thrive and increase in population greatly. However, by keeping the numbers of such middle preditors lower, these top sharks are protecting the sea life at the bottom of the food chain. When the smaller preditors thrive, their prey will decrease in numbers greatly, and combined with the over fishing of common fish, will all but wipe them out.
Global warming can affect marine life in a number of ways. Firstly, the warmer temperature of the air means that more storms are likely to occure. These storms are particularly damaging for coral reefs. Hundreds of years of growth can be destroyed in just a few hours. Another way in which it damages the marine life is that the warmer climate mealts away the ice caps which thousnands of marine life, as well as land animals such as polar bears, depend on. This damage to the reaf and to the ice caps also means that it damages the habitats of thousands of species of different marine life, making it harder for them to reproduce, grow, hunt and feed, and hide from preditors.