It is a wonderfully clear expression, used by a U.S. biologist about the impact of bottom trawling. "Imagine using a bulldozer to catch songbirds for food — that's what it's like," marine biologist Sylvia Earle says. "After a trawler has gone by, it looks like a superhighway, it's just flat. Nobody's home. A few fish may swim in and out but the residents, those that occupy the substrate, they're just smothered, they're crushed. It's like paving them over."

Perhaps it is the kind of comparison we should consider more often — after all, the oceans have been a case of out of sight, out of mind for far too long. We've dumped our sewage into the sea for generations, and have used it to dispose of everything from offshore drilling fluid to munitions.

We have dragged bottom trawls back and forth across it so many times that it is — as it was earlier this year — a small miracle when scientists actually find an untouched area of bottom corals.

We have continued to believe that the greatest harm to the sea has been the fishing vessels that bob on the surface, and their ever-shrinking catches. But we regularly draw the line at questioning the role of our methods of fishing.

Consider, for a moment, an on-land comparison. Imagine that you were hunting rabbits, and you knew that they particularly liked living and eating in alder thickets. You could create a system that knocked over all the alder trees and netted up all the rabbits, and that would work really well the first year you used it. The second year, there would be no alder trees and, frankly, no rabbits at all.

Such is the way things go with destructive technologies — and there are plenty who would argue that, as destructive technologies go, bottom trawling is pretty close to the top of the list.

Problem is, you'd see the decimated alders. Since we don't see the ocean floor, we can glibly pretend that the damage doesn't really exist.

Earle has seen the ocean floor — she's led more than 60 deep-sea expeditions, and has seen the damage with her own eyes on a regular basis.

Certainly, bottom trawling is not the only issue facing our fishery. It is a method that is heavily used outside the 200-mile limit, and, to put it bluntly, one that we use inside the 200-mile limit as well. As with most things in the fishery, there are no real good guys in the bottom-trawling business, nor any clean hands.

The ocean is a tremendously complex system, one that we know nowhere near enough about. But you can see right away what happens when you decide to clearcut a forest — the results aren't much different between a forest of trees and a forest of deep-sea coral, except for the fact the coral grows much, much more slowly.

This is an edited version of a June 1 editorial in the Telegram, St. John's, (Newfoundland).

© 2006 The Toronto Star