Scientist Richard Haedrich says bottom trawling is destructive to marine habitat.

U.S. President George W. Bush's endorsement of a ban on deep-sea bottom trawling puts pressure on Canada to follow suit, ecologists and scientists say.

In a memo sent Tuesday to his secretaries of state and commerce, Bush said the U.S. will promote sustainable fisheries and work with other nations and groups to halt bottom trawling, widely described as destructive to marine habitat.

The United Nations General Assembly was to begin debating a resolution Wednesday to ban deep-sea bottom trawling.

Trawlers from such countries as Portugal, Spain and Russia scrape up the ocean floor without any regulation outside of Canada's territorial waters on the Grand Banks, off the coast of Newfoundland.

Canadian trawlers do not go into international waters, but Ottawa has yet to support a ban on bottom trawling in those waters.

Mark Butler, marine issues co-ordinator with the Halifax-based Ecology Action Centre, said Canada is afraid to take a stand against international trawling because it will then face pressure to do the same within its own waters.

"It certainly upsets us that it appears one sector of the fishing industry is setting Canada's foreign policy," Butler told CBC News.

Federal Fisheries Minister Loyola Hearn has in the past said he does not like bottom trawling.

A spokesman in his office said Tuesday that Hearn is still considering Canada's stance.

Richard Haedrich, a marine scientist at Memorial University in St. John's, said draggers are killing offsome fish species at rapid rates.

"The deep sea is under pressures that it's never been under before," said Haedrich, who co-wrote a report published in the journal Nature earlier this year that reported alarming declines in marine species.

Haedrich said Canada should join a ban because, he said, deep-sea fish habitat that took thousands of years to form in the North Atlantic can be destroyed in seconds.

"The effect is as though you took a great big bulldozer and dragged it across the ocean bottom," Haedrich said.

Other nations that support a ban on bottom trawling include Australia, Germany, France and the United Kingdom.