WASHINGTON – To protect both exotic species and the ocean floor, the government should close some areas to fishing vessels that trawl thousands of feet below the surface for fish and shellfish, researchers said Monday.

“The lack of area-specific data on the effect of trawling and dredging gear is insufficient justification to postpone management of fishing effects on sea floor habitat,” the National Academy of Sciences said in a report.

The academy recommended that the National Marine Fisheries Service, which is charged with protecting fish and shellfish and their ocean habitats, put fragile areas off-limits to fishing. To minimize damage to the ocean floor, trawlers also should be required to modify some of the strong winches, cables and engines that can reach to depths of 3,000 feet and beyond.

“Closed areas are necessary to protect a range of vulnerable, representative habitats,” the report said. “Gear restrictions or modifications that minimize bottom contact can reduce habitat disturbance.”

It also said regional fishery councils that now manage most of the marine fisheries in U.S. waters should be tapped to help decide how to manage the sea floor habitats.

In 1996, Congress passed a law requiring the councils to identify essential habitat for each fish stock they manage in an effort to minimize the harm caused by trawlers’ mobile gear.

Trawling off the coasts of the United States began in the early 1900s, mostly along the Atlantic coast and the Gulf of Mexico. It also has spread to the Pacific coast, particularly in the Northwest and Alaska.

“Bottom trawling and dredging cause profound harm to many sea floor ecosystems,” said Elliott Norse, president of the Marine Conservation Biology Institute in Redmond, Wash., who blamed the councils for failing to prevent the loss of marine life among fisheries.

He recommended the federal government ban the use of large roller and rock-hopper gear on trawl nets in federal waters.

Rep. Joel Hefley, R-Colo., plans to introduce a bill Tuesday aimed at protecting coral and rocky habitats. The measure would limit to no more than 8 inches in diameter the large rubber discs or steel bobbins that are used with “roller trawls” or rock-hoppers to scrape the seabed with heavy nets.

“Rock-hopper gear destroys habitat that rockfish and other marine fish need for their survival,” said John Warner, a commercial fisherman and spokesman for the Coos Bay, Ore.-based West Coast Fishermen’s Alliance.