According to some environmentalists, the world's ocean fishing areas are an example of the "tragedy of the commons." Commons are unowned areas open to all; the oceans are open to the fishing fleets of all nations or, in coastal areas, an unlimited number of domestic fishermen. Since they have no property right to the fish, commercial fishers have no incentive to conserve them; instead, they are in competition to harvest as much as possible -- with devastating results.

• An estimated 70 percent of the world's fisheries are either depleted or near collapse, according to the United Nations.

• Species of fish that were once considered to have little economic value -- called trash fish -- make up an increasing share of the catch as more desirable species become scarce.

• In the Atlantic Georges Bank area, for example, dogfish made up 2 percent of the catch in 1963 but 45 percent in 1990, while codlike fish, which were 53 percent of the 1963 catch, were only 15 percent of the 1990 take.

• Governmental attempts to limit the types of nets used or the length of fishing seasons have had little effect, due to new technologies that allow harvesting more fish in less time.

However, government regulators are beginning to understand that access to fisheries must be limited and fishermen given a vested interest in conserving fish populations.

• New Zealand, for example, has created a system of enforceable rights to a share of fishery catches known as Individual Transferable Quotas that fishermen can trade or sell.

• Experts suggest creating common property rights in fisheries, controlled by defined groups of fishermen who would receive the benefits of conservation.

• Alternatively, fishermen could receive private property rights to defined areas of the ocean or seabed or specific populations of fish.

Technologies that have become commercially affordable, such as sonar and satellite tracking, make marking boundaries and tagging fish to identify their owners practical.

Source: Michael De Alessi, "Emerging Technologies and the Private Stewardship of Marine Resources," January 1996, Center for Private Conservation, Competitive Enterprise Institute, 1001 Connecticut Avenue, NW, Washington, DC 20036, (202) 331-1010.