Big fish are mostly gone: our demand for large amounts of inexpensive fish is emptying the ocean.

It's common knowledge that we are running out of oil. What's not so well known is that we are also running out of big fish.

The realization that stocks of big fish--marlin, sharks, swordfish, and tuna--are declining rapidly is beginning to sink in. The UN Food and Agriculture Organization considers about 75 percent of all fish fully exploited, over-exploited, or depleted.

The crisis can be seen most clearly across the Pacific, where catches are shrinking along with the average size of the fish. Today a 70-pound swordfish--too young to have reproduced--is considered "a good-sized fish" and can be legally landed in the US. Just a few short decades ago swordfish averaged 300-400 pounds and could be caught close to shore with a harpoon.

In the last two years, the Pacific has seen quotas, restrictions on catches, and even moratoriums. The US longline fleet had to shut down for the second half of 2005 in the Eastern Pacific. Japan and China were not far behind.

Just last December, a new international body with the unwieldy name Western and Central Pacific Fishery Commission imposed a freeze on further efforts to catch big-eye and albacore. It is widely documented that these two species have recently joined the southern bluefin tuna on the overfished list. Shark finning has also caused numerous shark species to decline as well and a few sharks, such as the great white, are considered vulnerable to extinction.

Recent scientific reports document that the total biomass of these large fish has declined by about 90 percent in the Pacific since 1950--about the time that new technologies allowed us to fish areas of the ocean we'd previously been unable to exploit fully.

The recent announcement by the US government that yellowfin tuna is also being overfished in Pacific will undoubtedly send a shockwave throughout the US and the Pacific. We are now faced with incontrovertible evidence that these lions and tigers of the sea--the ones we feed our children for lunch--are disappearing fast.

The days of three cans of tuna for a dollar, a vivid memory from my childhood, ate long gone. Imagine the day when cans of tuna, now a staple food source for millions of Americans, can no longer be found. That day may not be far off.

That's bad news for the dozens of impoverished Pacific island nations that have leased their national waters at bargain basement rates to foreign industrial longline vessels to catch and export their fish primarily to the US, Japan, and the EU. For some of these nations, licensing fees contribute as much as 70 percent of their GDR When these fish stocks collapse, millions of people throughout the Pacific will sink even further into poverty. Canneries are already cutting their hours or even shutting down for want of fish. Stories abound of crews mutinying or being abandoned in foreign countries by captains who couldn't pay them.

The solution is to catch fewer fish and pay more for them, while staying out of critical areas of the ocean. It only seems fair that the countries with the remaining fish should receive a far larger share of their $2 billion a year resource and still have some of the big fish around to attract far more lucrative game fishing tourism. The US has taken the right step by restricting longline fishing for tuna in the Eastern Pacific and banning it on the West Coast. It's time to put pressure on other countries to do the same. Otherwise we may be adding these fish to the endangered species list.

Robert Ovetz, PhD is the Save the Leatherback Campaign Coordinator with the US-based Sea Turtle Restoration Project.