2 On average, fish and other seafood account for 6 per cent of the total proteinand 17 per cent of the animal protein in the human diet. If this seems small, itshould be remembered that on a world basis most (65 per cent) protein comesfrom plants, chiefly cereals, beans and peas, nuts and oilseeds. Meat accounts for16 per cent and milk products for 9.5 per cent of the average total protein intake.
3 International statistics are a little misleading. Many communities in countriesnot otherwise notable for fish eating depend heavily on seafood, whether forsubsistence, income or both. Besides, the cultural and aesthetic importance ofseafood is at least as great and possibly much greater than its nutritionalimportance. What dish is more symbolic of expensive luxury than caviar?
4 There are no world figures for domestic trade in fish and fishery products,but it is clear from export figures alone that trade in seafood is both substantial andrapidly growing. In 1978 seafood exports reached almost $11,000 million, anincrease of 15 per cent over the previous year. In the 1980s nineteen countries, sixof them developing (Mexico, Peru, India, Thailand, Indonesia and South Korea),each earned $100 million or more a year from fish exports. Norway, Canada andDenmark each earned more than $600 million a year from their seafood exports.
5 Unfortunately use of fisheries is often not sustainable and their contributionto national diets and incomes is likely to diminish. The result of past and presentoverfishing is that the annual world catch is around 25 million tonnes (or about aquarter) lower than it might otherwise have been. At least 25 of the world's mostvaluable fisheries are seriously depleted. Many more are now so fully exploitedthat they can be expected to become depleted within a decade or so, because of theeffects of exploitation, either alone or in combination with those of pollution andhabitat destruction.
6 Yet an even bigger waste is the accidental capture and killing of non- targetanimals. For every tonne of shrimp landed at least three tonnes of fish are thrownaway dead. This is probably an underestimation. In the Gulf of Mexico the ratio offish discards to caught shrimp ranges from 3:1 to 20:1, largely depending onwhether the shrimp are trawled inshore or offshore. In 1976 the world catch ofshrimp was 1.3 million tonnes. Even assuming that some of the fish caught withthem were landed and marketed, it is still likely that at least 6.5 million tonnes offish were destroyed by shrimp trawling alone. Countries such as India are probablylosing 980,000 tonnes ot fish a year, Thailand 548,000 tonnes a year, Mexico andIndonesia each 360,000 tonnes a year, and so on. A lot of protein is beingneedlessly wasted.
7 It can no longer be assumed that depleted fish stocks will recover to their fullpotential. There are three factors obstructing their recovery. First, the spawningfishes and juveniles may continue to be caught by industrial fisheries (which takefish for conversion to animal feed). Second, ecosystem dynamics can change andanother species may take over because the depleted species can no longer competeeffectively with it. Third, habitats essential for spawning or as nurseries are beingdegraded or destroyed outright.
8 Wetland destruction is also a major problem along the middle Atlantic coast,but it is overshadowed by direct kills of fish and other marine animals. Heavyrecurrent pollution of the New York Bight is responsible for an unusually highincidence of fin rot disease in winter flounder and of 'shell disease' in Americanlobster and rock crab. Massive kills are caused by recurrences of anoxicconditions, ie severely reduced dissolved oxygen levels due to excessive inputs ofnutrients, largely via municipal wastewater discharges. Billions of organisms,including lobsters, surf clams, crabs, hake, winter flounder and sea bass, have beenkilled by these conditions. Other fish kills are due to municipal or industrialdischarges. In Virginia in 1973, 7.5 million fish were killed in one incident due toover-chlorination of waste effluent. The total cost of fish, crustacean and mollusckills in the region is estimated to be tens of millions of dollars a year.
9 Such problems are not restricted to coastal wetlands. In many parts of theworld coral reefs are also under attack from destructive fishing methods (includingthe use of dynamite), excessive collection of corals, shells and other coralorganisms, extraction of coral sand from lagoons, development of lagoons, oilpollution, siltation from erosion inland, pesticides, heat pollution, brine pollution(from desalination plants) and sewage pollution. Entire reefs in the Philippineshave been removed for building foundations and roads. Reefs near towns havebeen stripped of corals for ornament, and those near sugar refineries have beenseverely degraded. In Sri Lanka repeated removal of coral reef for the productionof lime is so extensive that a local fishery has collapsed; mangroves, small lagoonsand coconut groves have disappeared; and local wells have been contaminatedwith salt.
10 Action On Oceans
2 A major difficulty in the conservation of marine environments is that they arenot self-contained entities but parts of a continuum extending from the land to theopen ocean, and from one part of the ocean to another. The oceans have theirboundaries, but they are subtle and do not always correspond with popularconceptions of them. Currents, upwellings, salinity and temperature differences canact as barriers. The coast, by contrast, often unites rather than separates land andsea.
3 Governments and their resource management institutions generally havefailed to recognize this phenomenon. Indeed most of the problems facing the life ofthe seas stem from the failure of human politics and administrations to adjust to theecological realities of the seas. Thus the decline of fish such as herring is due lessto ignorance of the animals' biology or of the environments of which they are partthan to the weaknesses of the human institutions governing their exploitation. Inmany cases the scientific advice on the management of such fisheries has beensound, if a little mealy mouthed. But fishermen vote and governments have oftenbeen reluctant, until too late, to take steps that would put some fishermen out ofwork but would enable the remainder to earn their living from the sea virtuallyindefinitely.