Marine Life Facing Extinction
Human depredations on the sea have led to extinction of several large sea animals such as whales, sharks, rays, dolphins and turtles. Some of the animals such as whitetip sharks, American sawfish or the once “common” skate, numbers are down as much as 99 per cent. Most of the fishes the human would like to eat are vanishing fast. Number of Puget Sound’s salmon have come down drastically. Red snapper, bluefish and menhaden have been overfished. Why is this happening? What is happening to the fishes in the oceans? Overfishing is one reason. We are pumping massive amounts of chemical and industrial pollutants in the seas through our rivers. These
are affecting the oxygen levels under water and impacting temperature. Rise in emission of carbon dioxide has led to rise in acidity of oceans. Normally, the oceans have absorbed around 30% of the carbon dioxide released by humans all through the pre-industrial era. If the emissions are not cut, the ocean acidity is likely to rise 150% by 2050. This highest ever during the last 20 million years. The rising acidity will make life difficult for animals that live encased in carbonate shells. The runoff of nutrients from land, in the form of fertilizers and sewage, coupled with rising temperatures have triggered in recent years an explosion of dead zone, low oxygen areas where few species can survive. Dead zones are mainly found at the mouth of mighty rivers or heavily populated coastal areas.
However, not all will vanish. While some species vanish, some others gain. For instance jellyfish thrive in polluted waters. So new empires of jellyfish would rise. But our cheating of seas is leading to severe famine of sea food for humanity. We are emptying the oceans of fish at a rate they cannot be replaced, replenished or reproduced. If the pace at which we are fishing, the day when the seas could be without fish is not more than 40 to 50 years from now. (Extracted and reworded from Newsweek’s cover story titled ‘The Death of Our Oceans’, dt. May 21, 2012)