| Not that long ago, fishermen, politicians and even scientists saw the oceans as something like an all-you-can-eat buffet. No matter how much we took out, there seemed to be more waiting for us. We've since learned the hard way that there are limits to what we can take.
In Canada, our lesson came when Atlantic cod stocks collapsed and the federal government had to close the fishery in 1992. The moratorium was to last two years, but now, 10 years later, all indications are that the stocks are in worse shape than they were a decade ago. We may have passed a threshold for recovery.
Unfortunately, the lesson doesn't seem to have stuck. Scientists now routinely warn that fish stocks are in peril. Yet catch quotas are not being reduced and there seems to be little will on the national or international level to seriously tackle the problem. Recently, the International Council for the Exploration of the Seas (ICES) warned that some European cod stocks could face extinction unless there is a total ban on cod fishing in Europe. Stocks in the North Sea are at historic lows, with the estimated weight of mature cod having dropped from 270,000 tonnes in 1977 to 38,000 tonnes this year. Scientists say that's less than half of what is required to sustain any sort of fishery. Experts with ICES originally recommended that cod fishing be banned for at least four years to allow stocks to recover. However, under pressure from 20,000 U.K. cod fishermen, the ban recommendation has since been downgraded to a "severe restriction" and may be further downgraded before the regulations come into effect.
Similar problems are occurring around the world. As a recent article in the science journal Nature points out, "When push comes to shove, (in fisheries management) it seems that short-term economic interests steamroller scientific arguments." It's a dangerous trend, because fish stocks that have already collapsed are having trouble rebuilding. According to an analysis of 90 fish stocks done by biologist Jeff Hutchins of Dalhousie University in Halifax, some fish populations have failed to noticeably recover even 15 years after their collapse.
Part of the problem is that, even if a fish stock is protected, it can still face pressure from "bycatch," which refers to species that are caught accidentally while fishermen are searching for other stocks. That's what has happened to the barndoor skate, which has been driven to near extinction by being caught in trawling nets designed for cod.
Bottom trawlers are actually part of a larger problem as well because they don't just catch non-target species, they also trash the sea floor and make it more difficult for many species to recover. Yet for years, a myth has persisted that bottom trawling is actually good for the ocean. Some fishermen have even gone so far as to say that it's like "farming" the ocean floor. The theory was that trawlers removed larger, long-lived species, thereby allowing smaller, shorter-lived species like marine worms to flourish. These could then act as food for commercially valuable fish like sole.
That bizarre theory has finally been put to rest. In a paper to be published in the Marine Ecology Progress Series, researchers report that their study of 27 trawling sites in the North Sea found trawling to have no impact on marine worm populations. In addition, other studies have found that trawlers have heavily damaged both seagrass meadows off the coast of Spain as well as cold-water corals in the Atlantic.
Without serious changes to both the way we fish and the amount of fish we catch, more stock collapses in the near future are a foregone conclusion. With the lack of national and international will to change, consumers have an opportunity to help the situation by choosing to eat only fish whose stocks are not depleted. A handy guide is available online at the Monterey Bay Aquarium Web site at http://www.mbayaq.org/cr/seafoodwatch.asp .
Science Matters is a regular feature by writer, geneticist and television host David Suzuki. To discuss this topic with others, visit the discussion forum at www.davidsuzuki.org. |
