Temps de lecture :5 minutes
For decades governments tried to save specific fisheries by restricting the catch of individual species. Sometimes this worked; sometimes it failed and fisheries collapsed. In recent years, support for another approach—the creation of marine reserves or marine parks—has been gaining momentum. A network of marine reserves is defined as “a set of marine reserves within a biogeographic region, connected by larval dispersal and juvenile or adult migration.” Reserves serve as natural hatcheries, helping to repopulate the surrounding area. (1)
In 2002, at the World Summit on Sustainable Development in Johannesburg, coastal nations pledged to create national networks of marine parks, which together could constitute a global network of such parks. At the World Parks Congress in Durban in 2003, delegates recommended protecting 20–30 percent of each marine habitat from fishing. This would be up from 0.5 percent of the oceans that are currently included in marine reserves of widely varying size. It compares with the 12 percent of the earth’s land area that is in parks. (2)
A U.K. team of scientists led by Dr. Andrew Balmford of the Conservation Biology Group at Cambridge University analyzed the costs of operating marine reserves on a large scale based on data from 83 relatively small, well-managed reserves. They concluded that managing reserves that covered 30 percent of the world’s oceans would cost $12–14 billion a year. This did not take into account the likely additional income from recovering fisheries, which would reduce the actual cost. (3)
At stake in the creation of a global network of marine reserves is the protection and possible increase of an annual oceanic fish catch worth $70–80 billion. Balmford said, “Our study suggests that we could afford to conserve the seas and their resources in perpetuity, and for less than we are now spending on subsidies to exploit them unsustainably.” (4)
Coauthor of the U.K. study Callum Roberts, of the University of York, noted: “We have barely even begun the task of creating marine parks. Here in Britain a paltry one-fiftieth of one percent of our seas is encompassed by marine nature reserves and only one-fiftieth of their combined area is closed to fishing.” Yet the seas are being devastated by unsustainable fishing, pollution, and mineral exploitation. The creation of the global network of marine reserves—“Serengetis of the seas,” as some have dubbed them—would create more than 1 million jobs. Roberts went on to say, “If you put areas off limits to fishing, there is no more effective way of allowing things to live longer, grow larger, and produce more offspring.” (5)
Jane Lubchenco, former President of the American Association for the Advancement of Science, strongly underlined Roberts’ point when releasing a statement signed by 161 leading marine scientists calling for urgent action to create the global network of marine reserves. Drawing on the research of scores of marine parks, she said: “All around the world there are different experiences, but the basic message is the same: marine reserves work, and they work fast. It is no longer a question of whether to set aside fully protected areas in the ocean, but where to establish them.” (6)
The signatories noted how quickly sea life improves once the reserves are established. A case study of a snapper fishery off the coast of New England showed that fishers, though they violently opposed the establishment of the reserve at first, now champion it because they have seen the local population of snapper increase 40-fold. In a study in the Gulf of Maine, all fishing methods that put ground fish at risk were banned within three marine reserves totaling 17,000 square kilometers. Unexpectedly, scallops flourished in this undisturbed environment, and their populations increased by 9–14 times within five years. This population buildup within the reserves also greatly increased the scallop population outside the reserves. The group of 161 scientists noted that within a year or two of establishing a marine reserve, population densities increased 91 percent, average fish size went up 31 percent, and species diversity rose 20 percent. (7)
While the creation of marine reserves is clearly the overriding priority in the long-standing effort to protect marine ecosystems, other measures are also required. One is to reduce the nutrient flows from fertilizer runoff and untreated sewage. These increased nutrient flows cause huge algal blooms that then die off and in the process of decomposition absorb all the free oxygen in the water, leading to the death of local sea life. Today there are some 146 dead zones, either seasonal or chronic, scattered in the world’s oceans from the Gulf of Mexico to the Baltic Sea to the east coast of China. (8)
The Gulf of Mexico dead zone near the mouth of the Mississippi River is one of the best known. This New Jersey–size area substantially reduces the marine diversity and yield of this historically productive body of water. Better control of nutrient runoff can be achieved through the adoption of such farming practices as minimum tillage and no-till, through the precise application of fertilizer to meet crop needs, and through planting buffer and filter strips along the Mississippi River and its tributaries. (9)
In the end, there is a need for governments to eliminate fishery subsidies. There are now so many fishing trawlers that their catch potential is nearly double any yield the oceans can sustain. Managing a network of marine reserves governing 30 percent of the oceans would cost only $12–14 billion—substantially less than the $15–30 billion that governments dole out today as subsidies to fishers. (10)
1. Definition of marine reserves network from “Scientific Consensus Statement on Marine Reserves and Marine Protected Areas,” presented at the AAAS annual meeting, 15-20 February 2001, initial signatories include Steven Gaines, Jane Lubchenco, Stephen Palumbi, and Megan Detheir, p. 2.
2. Andrew Balmford et al., “The Worldwide Costs of Marine Protected Areas,” Proceedings of the National Academy of Sciences, vol. 101, no. 26 (29 June 2004), pp. 9,694–97; “Costs of a Worldwide System of Marine Parks,” press release (York: The University of York, 12 July 2004).
3. Balmford et al., op. cit. note 44; Tim Radford, “Marine Parks Can Solve Global Fish Crisis, Experts Say,” Guardian (London), 15 June 2004.
4. Balmford op. cit. note 44; Radford, op. cit. note 45.
5. Radford, op. cit. note 45; Richard Black, “Protection Needed for ‘Marine Serengetis,’” BBC News, 6 August 2003; Balmford et al., op. cit. note 44.
6. American Association for the Advancement of Science (AAAS), “Leading Marine Scientists Release New Evidence that Marine Reserves Produce Enormous Benefits within Their Boundaries and Beyond,” press release (Washington, DC: 12 March 2001); “Scientific Consensus Statement,” op. cit. note 43.
7. AAAS, op. cit. note 48; “Scientific Consensus Statement,” op. cit. note 43.
8. R. J. Diaz, J. Nestlerode, and M. L. Diaz, “A Global Perspective on the Effects of Eutrophication and Hypoxia on Aquatic Biota,” in G. L. Rupp and M. D. White, eds., Proceedings of the 7th Annual Symposium on Fish Physiology, Toxicology and Water Quality, Estonia, 12–15 May 2003 (Athens, GA: U.S. Environmental Protection Agency, Ecosystems Research Division, 2004); United Nations Environment Programme (UNEP), GEO Yearbook 2003 (Nairobi: 2004).
10. Organisation for Economic Co-operation and Development, Review of Fisheries in OECD Countries: Policies and Summary Statistics (Paris: 2003), pp. 55–56; World Wildlife Fund, Hard Facts, Hidden Problems: A Review of Current Data on Fishing Subsidies (Washington, DC: 2001), pp. ii; Balmford et al., op. cit. note 44; Radford, op. cit. note 45.
Restoring the Earth, in Plan B 2.0: Rescuing a Planet Under Stress and a Civilization in Trouble, Chapter 8 (NY: W.W. Norton & Co., 2006)
Lester R. Brown
Copyright © 2006 Earth Policy Institute