Water covers almost 70% of the earth's surface. Many different organisms live in our planet's waters. Apart from natural
enemies, these organisms are often threatened by human activities. Besides the usual sorts of fishing, humans more and more build boats which are capable of catching smaller and smaller
fish. Some species are threatened by this kind of fishing, because it is done on
such a large scale. These fish are unable to grow up and multiply before being catched, so populations will be unable to recover to their normal numbers.
Big fish, like sharks and wales, are also threatened by fishing nets.
They can get stuck or deadly wounded in one of the active or abandoned fishing nets floating around our seas and oceans.
Undersea mining is a second threat by humans. This results in noise and waste pollution for many marine
animals. Some dolphins strand because they become confused by the
noise caused by undersea mining, drilling, boats and other human activities at sea. Many of these activities and industrial products cause pollution in the form
of toxics.
A third threat to marine life are
other forms of hunting by humans. Seals in Canada and other regions are still beaten to death each year for their fur,
and wales are still hunted with harpoons. This whaling continues mostly under the pretext of japanese scientific research.