25 de febrero del 2001
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Report

Vulnerable Oceans

By Danielle Knight*

Less than one percent of the world's oceans are protected through areas set aside for natural conservation, warn leading scientists

WASHINGTON - Some 150 scientists and specialists prominent in the study of the oceans emitted a call for the immediate establishment of marine reserves to replenish the planet's depleted seas at a conference of the American Association for the Advancement of Science, in San Francisco, California.

''The declining state of the oceans and the collapse of many fisheries creates a critical need for new and more effective management of marine bio-diversity, populations of exploited species and overall health of the oceans,'' say the experts in consensus statement.

''Marine reserves are a highly effective tool that can help alleviate many of these problems''.

Most marine scientists believe the seas are in serious trouble. They view coral bleaching, changes in species composition, toxic algal blooms, and fisheries collapse as symptoms of complex but fundamental alterations in the health of marine ecosystems.

Intense fishing activity, along with a rise in marine trade, the construction of ports, and growing tourism all contribute to drastic transformations of marine and coastal areas.

In Latin America, which is home to the second largest coral reef in the world (Belize) and one of the top five fishing industries (Chile and Peru), the total fish catch was 21 million tons in 1995, or 20 percent of the world total, according to United Nations reports.

Currently, less than one percent of the world's oceans are protected in reserves, where all biological resources are protected through prohibitions on fishing and the removal or disturbance of any living or non-living marine resources.

But scientists say that the few existing marine reserves have proven to be a useful tool for restoring ocean health.

''Marine reserves work and they work fast,'' says Jane Lubchenco, a professor at Oregon State University who co-chairs a group of international scientists that have been studying marine reserves since 1997.

''It is no longer a question of whether to set aside fully protected areas in the ocean,'' she says, ''but where to establish them''.

Some 30 countries have designated areas as marine reserves, but they do not all follow the same guidelines. Marine reserves are sometimes called ''ecological reserves'', or ''no-take areas'' which are different from other protected marine areas because they do not allow any extractive activities.

Robert Warner, a scientist with the University of California in Santa Barbara who studies marine reserves, points out that just one or two years after the creation of the conservation areas, the average population densities of marine life were 91 percent higher.

''The results are startling and consistent,'' he said.

Biomass was 192 percent higher and the average size of organisms was 31 percent higher, Warner reports, adding that species diversity also increased by 23 percent.

The size and abundance of exploited species also increases in areas adjacent to reserves, according to Callum Roberts, a marine scientist at Harvard University.

Marine reserves differ from parks on land because they serve as natural hatcheries, replenishing populations regionally by the spillover of larvae beyond reserve boundaries.

Most marine species move through the water as larvae or spores, moved by tides and currents. Dispersal distances of 20 to 50 kilometers are not uncommon and dispersal of 500 to 1,000 kilometers is possible in some cases due to currents, say scientists.

Fishers usually vigorously resist the creation of marine reserves at first, but once these communities realize that the reserve actually increases the size and abundance of fish near the reserves, they end up supporting the conservation effort, says Lubchenco.

''While fishermen may lose access to some areas, they will reap the benefits outside the reserves,'' she says.

Roberts points to the case in New Zealand where, despite violent opposition at the outset, fishers have now become the champions of reserves where they have seen populations of snappers increase 40-fold.

In the United States, three areas totaling 17,000 square kilometers in the Gulf of Maine in 1994 were closed to all fishing methods that put a fish species, known as groundfish, at risk. Within five years, says Roberts, their populations rebounded to nine to 14 times their density in fished areas. Scallops also flourished in the undisturbed habitat.

In Latin America, one of the best known reserves is that of Ecuador's Galapagos Islands, declared a Natural Heritage of Humanity site by the United Nations Educational, Scientific and Cultural Organization (UNESCO).

A 1998 law bans fishing by vessels from mainland Ecuador or other nations in the 140,000-square-km reserve. Only local fisherfolk may cast their nets, says the legislation, and 50 percent of the profits from tourism must go to conservation of the biodiversity of the islands and the surrounding seas.



* Danielle Knight is an IPS correspondent.

 

Copyright © 2001 Tierramérica. Todos los Derechos Reservados

 

 

External Links


A portal on marine ecosystems

Protected marine areas in the United States

About oceans (UNESCO - UNEP)

Data on protected marine areas

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