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.

Many people are under the mistaken impression that pollution is responsible for declines in marine species. Others may find it hard to believe that a shortage of desirable food fish even exists, because they still notice piles of Chilean sea bass and tuna fillets in their local fish markets. Why is commercial fishing seen as having little if any effect on the species that are being fished? We suspect that this perception persists from another age, when fishing was a matter of wresting sustenance from a hostile sea using tiny boats and simple gear.

   
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