Biology: The Dynamics of Life, California EditionChapter 5: Biological Diversity and ConservationIn the NewsHow Big of a Problem is Overfishing? What do cod, tuna, halibut, swordfish, and mackerel all have in common? Yes, they are fish, but recently they also have become a cause for concern. As the world population increases, so does the demand for seafood. Cod, tuna, and others are favorite catches for fishermen and favorite dishes for many people. Since the oceans cover such a vast area of Earth, it was once believed that they could provide an endless supply of seafood. Now, recent studies show that the oceans are being overfished and the delicate ecosystems that exist throughout the oceans are being disrupted. In May, Canadian researchers suggested that globally, the oceans have lost more than 90 percent of the large predatory fishes which include cod and bluefin tuna. How might this affect ocean ecosystems? One theory says that overfishing the top predators could cause "dead zones" - areas of complete ecosystem collapse, where microbes fill the void left by fish and invertebrates. Dead zones already have been found in the Gulf of Mexico, Chesapeake Bay, and the Baltic and Adriatic seas. Many scientists are somewhat reluctant to speculate on exactly how overfishing could affect marine environments because so little is actually known about marine ecosystems. Scientists do agree that overfishing is not the only thing causing a decline in fish populations. Pollution and overdevelopment of coastal land also affects the health of the oceans. However, one thing is certain, if fish populations fall below critical mass, they could lose the ability to reproduce and species would die out. Millions of people who rely on the fishing industry to pay their bills would be out of work. What are the solutions? Several steps are being taken to protect the big game fish. The Canadian government currently enforces a moratorium on cod fishing and has placed the Atlantic cod on their endangered species list. Throughout the world, more fish are being raised on farms and quotas on the number of fish being caught are being enforced. Fishing industry officials insist that researchers have overestimated the number of fish harvested and that these reports are attempts to put them out of business. Which group of people is correct? Is there a solution that would meet the needs of both the ocean's ecosystems and the fishing industry?
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