EDGARDO D. GÓMEZ
outlines the threats to coral reefs, mangrove swamps and seagrass beds as increasing coastal populations endanger the most productive parts of the oceans
Today's advances in mass communication and information technology have ensured that much of the world has heard of coral reefs, mangroves and seagrass beds. Over the last two years, for example, an educational programme about the International Year of the Reef reached a billion people. But their vital importance to coastal dwellers - especially marginalized ones - and their threatened condition in much of their range may not be adequately appreciated.
Some estimates suggest that over half of the planet's population - or about 3.2 billion people - lives and works within 200 kilometres of a coast; others calculate that over a third of the world's people live within 100 kilometres of one. While there may be debate over the exact figures, there is no disagreement that the coastal zone is consistently the most populous part of the world and that there is a continuing tendency for people to migrate to it from the interior of the continents. This tremendous flux of people is increasing the pressure on an already stressed area, and increasing contamination from sewage and industrial pollution, as well as agriculture.
Fisheries and other living resources of the sea are also concentrated in the narrow coastal zone. Some 90 per cent of the world's fisheries production comes from this zone, though the latter makes up only about 10 per cent of the world's oceans. This productivity is generally explained by the shallowness of the sea allowing adequate light penetration to drive photosynthesis, the recycling of nutrients and the subsidies of nutrient or energy received from the land. Several critical habitats are especially productive in the tropics: the fragile coastal ecosystems of coral reefs, mangrove swamps and seagrass beds.
The proximity of large human populations to the most productive parts of the marine realm is, alas, no accident: a natural affinity brings them together. But it causes critical problems in much of the developing world, the greater part of the planet.
Many television programmes have emphasized the aesthetic value of coral reefs. While this is good, the fact is that their productivity makes them more valuable to a greater number of people. This, however, has caused the greatest threat to them - overfishing, which often involves such destructive methods as the use of dynamite or other explosives and the application
of poisons to capture both ornamental and edible species. These are often used by errant entrepreneurs to maximize their profits, usually at the expense of the local population.
Overfishing is tied to population and poverty in many developing countries. The growth of population in coastal areas is remarkable - but there is no commensurate growth of the reefs or their resources. So more and more people are depending on the same number of reefs - or even fewer as they become degraded. It is difficult to reduce the number of people fishing the reefs, because they have no other way to earn their living. The pervasive poverty of many coastal dwellers in developing countries aggravates the situation. Many marginalized, landless people often end up on the water's edge, trying to eke out a livelihood from a common resource to which they have free access.
It is even harder to address the overexploitation that results from greater prosperity. As some developing countries progress, more and more people increase their buying power, and this raises demand for many commodities, not least marine living resources. Just increasing the demand for traditional food products strains marine production. But there is also a growing demand, especially in the Orient, for marine products as status symbols and for their 'magical' (read 'aphrodisiac') properties - something that fisheries managers may not have included in their models. Recently,
for example, pods of whale sharks feeding just outside reef areas in the Philippines have been caught and sold, reportedly for about $250 per animal. Entrepreneurs process the carcasses and sell the products to the growing Chinese market for as much as 25 to
50 times their cost. If the often poor, local fishers normally earn less than $20 a day from traditional fishing, what will stop them from exploiting the whale shark population to extinction in this way?
The culprits that destroy mangrove swamps for commerce tend to be the moneyed class. Half of the 500,000 hectares of mangroves that existed in the Philippines at the beginning of this century have already been converted to fish and shrimp ponds. If, in the past decade, the Government had not begun to impose stronger protective measures, we would probably be seeing the last of our mangroves. The ponds destroy traditional fishing grounds, removing a source of income from local communities by people who will be making profits at their expense. The displaced fishermen are not provided with alternative sources of income, apart perhaps for a handful employed as pond labourers. Neighbouring areas are made less productive, aggravating poverty and even reducing the catch of commercial fishing firms. The irony is that many shrimp producing areas are now desolate and unproductive because poor management led to the outbreak of diseases that destroyed the industry. There appears to be no cure for these pathogenic, luminous bacteria and there is widespread contamination of the substrate.
The seagrass beds, the least known and appreciated of the three coastal ecosystems, have only recently been recognized for being just as productive as the other two, if not more so. In the past, these generally unremarkable ecosystems were ignored and they are still often the unintended victims of human activities. Thus, many seagrass beds are inadvertently torn up or buried in coastal dredging operations. Sometimes they are deliberately buried under mine tailings. This happened, for example, on the island of Marinduque in the Philippines, and decades after the event the marginalized fishing people have still not received compensation from the mining company.
This is only a broad outline of some of the major issues relating to coastal environments in the tropics: the solutions would need a separate treatment. Many papers on the marine environment have focused on the physical aspects of environmental degradation - but more and more people are now realizing that the solutions to environmental problems are often not technological, but political and sociological.
Governments and world leaders must focus more on these aspects if we are to turn the situation around. Marine scientists like myself can only point the way and provide technical advice to the decision makers when it is needed and useful.
Professor Edgardo D. Gómez is Director of the Marine Science Institute, University of the Philippines.