The Effects of Human Activity on Marine Wildlife
Earth is the only planet in the entire universe that currently has the capability to house living creatures. Considering that 70% of this planet is covered in water, one would think the creatures inhabiting the planet would treat the water with the upmost care. However, this is incorrect. Homo sapiens, the most intelligent species on the planet, tend to treat the oceans as a place to retrieve free raw materials and a personal waste disposal. During human’s 200,000 year existence on earth, this species has managed to completely undermine the ecosystem of the marine world by introducing alien species to a certain habitat, destroying marine habitats, over-harvesting fish, and polluting the waters.
Often people knowingly, and unknowing introduce new species into an ecosystem in which these animals have no natural enemies. They compete with native wildlife for food, space, shelter, water and threaten the existence of native species. When people began to travel freely around the world, they carried with them other organisms. Some of these transplanted organisms spread rapidly, decimating populations of native species. Zebra mussels, for example, were introduced to the Great Lakes via the release of ballast water from ships coming into port. They have now spread to the Hudson River, and are out-competing native clams. Invasive or alien species are now drawing attention as an important vehicle of extinction. At one time, as many as 500 species of cichlids existed making Lake Victoria one of the most diverse lakes in the world. However, the number of cichlid species has now plummeted to just 200, mainly due to the Nile Perch. A side effect of the loss of cichlid species is that a significant number of them feed on detritus. With declining numbers of cichlids to feed on detritus, more unconsumed organic material was left to decay using up oxygen as it sank to the lake bed. Some areas of the lake,...