Just got the most recent issue of SciAm in yesterday's mail, there is an article on a topic I've posted about before...

Georges Bank--the patch of relatively shallow ocean just off the coast of Nova Scotia, Canada--used to teem with fish. Writings from the 17th century record that boats were often surrounded by huge schools of cod, salmon, striped bass and sturgeon. Today it is a very different story. Trawlers trailing dredges the size of football fields have literally scraped the bottom clean, harvesting an entire ecosystem--including supporting substrates such as sponges--along with the catch of the day. Farther up the water column, longlines and drift nets are snagging the last sharks, swordfish and tuna. The hauls of these commercially desirable species are dwindling, and the sizes of individual fish being taken are getting smaller; a large number are even captured before they have time to mature. The phenomenon is not restricted to the North Atlantic but is occurring across the globe.

Scientific American <a href="http://www.sciam.com/article.cfm?chanID=sa006&articleID=00017139-DB05-1EDC-8E1C809EC588EF21>(partial article)

This whole topic is very serious - whole layers of the world's ocean ecosystems are being wiped out, and the short and long term effects are not clear but certainly very bad. It's not like wiping out buffalo or passenger pigeons, which were serious enough but basically a single species, or even like the exctinctions of large mammals in North America after the last ice age. The removal of so many fish (and other organisms) of so many sizes and species, over such global areas, will have extreme consequences.

The large number of people who depend on fish for food and income is a minor (though of course still important) part of the problem. The disruption in food chains and overall ecology has a far greater potential for global problems. Somewhat like global warming, we don't really know exactly what the effects will be, but there is absolutely no doubt that this problem is caused by human activity.

SARS may yet end up being the story of 2003, but overfishing might be the story of the decade, if not the century.

(by the way, I don't think SARS is over yet. A global disaster has been averted by quick and firm action and coordinated effort by health authorities, but it could easily be something that falls back until we let our guard down, then rears up and bites us in the ass).