Environmental Problems, Their Causes, and Sustainability 1

new region, hoping that the overfished species willrecover.Overfishing is not new. Historical studies indicatethat some species were overfished beginning centuriesago. However, overfishing has greatly acceleratedwith the expansion of today’s large and efficient globalfishing fleets.According to the UN Food andAgriculture Organization,about three-fourths of the world’s 200 commerciallyvaluable marine fish species are either overfishedor fished to their estimated maximum sustainableyield. According to the Ocean Conservancy, “we arespending the principal of our marine fish resourcesrather than living off the interest they provide.” Analystswarn that some of these fisheries are so depletedthat even if all fishing stopped immediately it wouldtake up to 20 years for stocks to recover.Studies by the U.S. National Fish and WildlifeFoundation show that 14 major commercial fishspecies in U.S. waters such as some groundfishes (Figure14-26) have been severely depleted. Also, degradation,destruction, and pollution of wetlands, estuaries,coral reefs, salt marshes, and mangroves threaten populationsof fish and shellfish.Good news. In 1995, fisheries biologists studiedpopulation data for 128 depleted fish stocks and concludedthat 125 of them could recover with carefulmanagement. This involves establishing fishing quotas,restricting use of certain types of fishing gear andmethods, limiting the number of fishing boats, closingHarvest(thousands of metric tons)800600400200Source: NMFS01960 1970AbundanceHarvest80706050403020101980 1990 2000YearAbundance(kilograms/tow)Figure 14-26 Natural capital degradation: The harvest ofgroundfishes (yellowtail flounder, haddock, and cod) in theGeorges Bank off the coast of New England in the North Atlantic,once one of the world’s most productive fishing grounds, hasdeclined sharply since 1965. Stocks dropped to such low levelsthat since December 1994 the National Marine Fisheries Serviceshas banned fishing of these species in the Georges Bank.The closure helped. By 1999 populations of the major groundfishesbegan recovering. However, the fishery still remainsclosed because it has been so severely depleted. (Data fromU.S. National Marine Fisheries Service)fisheries during spawning periods, and setting asidenetworks of no-take reserves. So far we are not doingmost of these things.Should Governments Continue SubsidizingFishing Fleets? Too Many Boats ChasingToo Few FishGovernment subsidies given to the fishing industryare a major cause of overfishing.Overfishing is a big and growing problem because wehave too many commercial fishing boats and fleets tryingto hunt and gather a dwindling supply of the mostdesirable fish.It costs the global fishing industry about $120billion a year to catch $70 billion worth of fish. Governmentsubsidies such as fuel tax exemptions, pricecontrols, low-interest loans, and grants for fishing gearmake up most of the $50 billion annual deficit of theindustry. Without such subsidies, some of the world’sfishing boats and fleets would have to go out of businessand the number of fish caught would approachtheir sustainable yield.Continuing to subsidize excess fishing allows somefishers to keep their jobs and boats a little longer whilemaking less and less money until the fishery collapses.Then all jobs are gone, and fishing communities suffereven more—another example of the tragedy of the commonsin action. Some of the money could be shiftedfrom subsidies to programs to buy out some fishingboats and retrain their crews.xHOW WOULD YOU VOTE? Should governments eliminateall fishing subsidies? Cast your vote online at http://biology.brookscole.com/miller14.What Is Aquaculture? Feedlots of the SeaRaising large numbers of fish and shellfish in pondsand cages is the world’s fastest growing type of foodproduction.Aquaculture involves raising fish and shellfish for foodlike crops instead of going out and hunting and gatheringthem. It is the world’s fastest-growing type of foodproduction and accounts for about one-third of the fishand shellfish we eat. China, the world leader, producesover two-thirds of the world’s aquaculture output.There are two basic types of aquaculture. Onecalled fish farming involves cultivating fish in a controlledenvironment (often a coastal or inland pond,lake, reservoir, or rice paddy) and harvesting themwhen they reach the desired size.The other is fish ranching. It involves holdinganadromous species such as salmon that live part oftheir lives in fresh water and part in salt water in captivityfor the first few years of their lives, usually infenced-in areas or floating cages in coastal lagoons and300 CHAPTER 14 Food and Soil Resources