MIAMI — With dredging set to begin this weekend in the Port of Miami, researchers are scrambling to salvage a much larger than expected trove of delicate corals that were not in the original marine life rescue plan for the undersea area.

The researchers must be out of the shipping channel known as Government Cut by Friday, a much narrower window than expected for salvaging the coral. They have asked for an extension to complete their work, but so far have been denied one.

In the past few days, researchers say they have found thousands more specimens along sections of the channel beyond where the Army Corps of Engineers was obligated to remove large, important corals in preparation for the dredging. Most of those corals have been removed by the Army Corps of Engineers and, for the most part, have been transplanted onto other reefs.