BOSTON – Federal fishing regulators, bowing to opposition, have delayed a program that would have allowed New England fishermen to lease their unused fishing days to other boats.

NOAA Fisheries said in a statement Thursday that the plan is off the table through April 30, 2004, the end of the current fishing year. It is under discussion for next year.

Each boat is allowed a certain number of fishing days depending on past activity. The typical boat is now able to catch groundfish 70 days per year, a level that some fishermen say is barely worth it.

The agency’s proposal would have allowed some boat owners to lease their days at sea and stay home, earning money while avoiding costs, while other boat owners more reliant on fishing income could use those extra fishing days to increase their catch and profits.

But some fishermen had worried that the plan would lead to a consolidation of the fleet as small family-operated boats lease their fishing days to a relatively few larger ones. Others said the plan would lead to bigger catches overall at a time when the fleet is already catching too much and fish populations remain depleted.

In a letter to NOAA Fisheries last month, Massachusetts Sens. Edward M. Kennedy and John F. Kerry said the rule was being implemented without enough time to review its implications.

They said that “judging from the growing letters of opposition and concern regarding the [days at sea] proposal, its inclusion in the emergency rule appears to have had the opposite of its intended effect.”

The National Marine Fisheries Service proposed the plan in emergency regulations posted in the April 24 Federal Register.