CANADA'S seizure of a Spanish fishing trawler in international waters this month has helped to highlight the dwindling numbers of ocean fish.
The Rome-based United Nations Food and Agriculture Organization (FAO) reports that 70 percent of the world's fish stock is either fully exploited, overexploited, depleted, or trying to make a comeback.
''It's been 20 years just going down the tube and nobody taking it seriously,'' says Chris Newton, head of FAO's fisheries information and statistics service.
Fish are a key protein source for about a fifth of the world's population. As populations rise, the demand for fish increases. And that growing demand is causing problems for consumers.
''Prices are climbing. The availability of fish like swordfish is declining,'' explains Michael Sutton, vice president of the Washington-based World Wildlife Fund.
''If you go to any fish market in the world, the people who have worked there for some time will tell you that they've seen pretty major changes in their lifetimes,'' he says.
For example, squid, whiting, and mackerel stocks have increased, while cod, hake, and haddock have declined.
Vast industrial fleets have been trying to catch practically everything they can get their nets on for years. The fact that a Spanish vessel was fishing a couple of hundred miles off the coast of Canada -- not in its own home waters -- testifies to how serious the problem of overfishing is, says Mr. Sutton.
The world's countries ''have never developed the political will to manage fisheries as they should be, so that catches are sustainable,'' he adds. ''That's primarily because the fishing industry has been so politically powerful that any government managers that try to institute strict controls have been overridden and overruled by industry.''
International law regulating fishing must be strengthened, experts say. Participants at the upcoming UN conference on high-seas fishing expect to put finishing touches on a draft fisheries treaty to be signed in the fall. Environmentalists see the conference as an important opportunity for forceful action to reduce the depletion of ocean fish stocks.
The large number of fish brought to market is not the only problem. Between 17 million and 39 million tons of fish are tossed off boats every year, because they're too small or not in demand, the FAO says. Although they are returned to the ocean, these fish often die because they're out of water too long. ''That's an appallingly high waste of fish,'' says Matthew Gianni, fisheries expert for Greenpeace International.
Solving the problem of declining ocean stock will not be easy, experts say, but reducing the waste of fish is one step that can be taken. Other steps, they say, are elimination of subsidies, which prop up the fishing industry by $50 billion a year; protection of overfished stocks; and an increase in aquaculture.
''In the long run, it seems probable that most of the increased supplies will come from aquaculture,'' says the FAO in ''The Role of Fisheries in Food Security,'' a report released in January. ''The contribution from capture fisheries -- particularly marine capture fisheries -- will depend upon better management of capture fisheries and technological developments.''