Washington ? Research indicating that whales may have been much more plentiful in the North Atlantic could mean it will be years before populations recover to a level where hunting could resume. However, the finding is being questioned by scientists in both pro- and anti-whaling nations.

Commercial whale hunting is now banned because stocks were sharply reduced in more than a century of hunting. But some countries, including Iceland and Japan, want to resume the hunts.

If stocks were really much larger in the past, new hunts could be delayed by the International Whaling Commission until the whale population builds closer to original levels. The commission says hunting should not be allowed until the population reaches at least 54 percent of the ocean’s carrying capacity for the mammals.

Stephen R. Palumbi of Stanford University and Joe Roman of Harvard University used DNA analysis to estimate historical whale populations in the North Atlantic. They concluded that because of wide variation in whale DNA, stocks in the past were much larger than had been thought.

Using the totals from the new DNA study would require the moratorium on fin and humpback whales, at least, to be continued for 30 to 100 years, Palumbi said.