Before Trawling
After Trawling


Trawling- to fish with a long fishing line towed by a boat and supporting many smaller lines bearing baited hooks.



A new survey published in the Journal of Science says that almost every instance of marine ecosystem collapse is caused by over-fishing. Agricultural runoff and seafloor dredging throw the final blow, but over-fishing gets the ball rolling. Over-fishing does more than kill fish, it changes ecosystems forever because the fish are linked to so many other parts of the ecosystem. A good example is the harvesting of green sea turtles in the Caribbean and South Florida. This led to the breakdown of ecosystems in those areas. In 1607 the Chesapeake Bay was home to whales, manatees, five different species of sea turtles, oysters on shoals and reefs, and many types of sharks. Now all these creatures have disappeared from that area due to over-fishing. Some have become extinct and others are endangered. The Chesapeake Bay has become murky and filled with jellyfish and toxic red tides. Also, in the San Francisco Bay there once was strong commercial fishing, but it has disappeared because there is no longer fish living there. It is now only overrun with Asian clams and other species. The Gulf of Mexico and its surrounding bays also have a major problem. They are filled with “Dead Zones,” which are areas with oxygen-depleted water where nothing can live. In the U.S. these ocean problems began in the mid-1700s when forests were cleared and plantations were built. This did not, however, put a major dent in the health of the oceans. The main problems began in the early 1900s when fishing fleets began to dredge up the large oyster reefs. This dredging created the murky waters and “Dead Zones” we see today. Bottom trawls and scallop dredges destroy corals and sponges, making it harder for baby fish to survive without their “nurseries.” Blast fishing and Cyanide fishing also began. Blast fishing is when fishers explode homemade devices over coral reefs, which kills fish and damages coral reefs. Cyanide fishing is fishing with sodium cyanide. This makes tropical fish slow and clumsy, so they are easier to catch. It also kills off corals. Another method of fishing is using large nets to catch lots of fish at once. This causes a huge danger to dolphins, whales, and other ocean mammals who can get stuck in the nets and drown. As fishers run out of the major species of fish, they begin to turn to new species of fish, and even things like urchins, cucumbers, jellyfish, and barnacles. This slowly destroys those fragile species as well.