Content that new federal limits on catching swordfish will buoy the fish’s population, two environmental groups are ending their two-year campaign to convince restaurants not to serve swordfish. The National Marine Fisheries Service last week announced plans to close more than 100,000 square miles of the Gulf of Mexico and Atlantic Ocean to pelagic longline fishing, and a similar ban may be in the works for the Grand Banks off New England and Canada. SeaWeb and the Natural Resources Defense Council, which waged the campaign, are releasing some 700 chefs from their pledge not to serve Atlantic swordfish. One wholesale fish seller said the new restrictions could push the price of the fish up 50 percent; currently, swordfish can retail for more than $10 a pound.