(CNN) -- The federal government has reopened 4,281 square miles of federal waters off the coast of western Louisiana to commercial and recreational fishing, according to Jane Lubchenco, head of the National Oceanic and Atmospheric Administration.

The region being reopened represents 7.4 percent of the total area in the Gulf of Mexico that had been closed off prior to Friday.

More than 48,000 square miles of federal waters -- roughly 20 percent of the total federal waters in the Gulf -- remain closed to fishermen. At its height, the fishing ban resulting from the April 20 BP oil rig explosion stretched over 88,000 square miles, or 37 percent of federal Gulf waters, Lubchenco noted.

The western Louisiana waters represent the third area in the Gulf to be reopened to fishing. A region off the Florida peninsula was reopened on July 22, and another area off the Florida panhandle was reopened on August 10, according to Lubchenco.

Officials are "nibbling at the edges" in terms of reopening the Gulf waters after extensive testing, Lubchenco said, starting with areas that were the least contaminated.

"We feel completely confident that the (Gulf) seafood that is in the market now is safe for human consumption," she told reporters. But we will "continue to investigate the longer-term impacts this spill may have had."

Lubchenco said that in order for an area of the Gulf to be reopened, no oil can be present or expected to be present in the forseeable future. Water samples taken from the area must pass both a sensory and chemical analysis.

She also stated that the NOAA -- in conjunction with the Environmental Protection Agency -- will continue to test seafood from reopened areas of the Gulf.

In a separate announcement, Louisiana officials stated that a project to monitor shrimp trawling vessels in St. Bernard Parish waters would conclude on Friday.

The project began on August 12.

"We've encountered dozens of shrimp vessels at work in St. Bernard Parish," said Jeff Dauzat, an environmental scientist with the Louisiana Department of Environmental Quality. "All vessels encountered ... have been inspected and no indications of oil have been noted on nets or in the catch."

The federal and state announcements came roughly three weeks after BP plugged its crippled Macondo oil well in the Gulf with cement and mud from above. Crews are currently "fishing" for pieces of drill pipe that need to be removed from inside the well's blowout preventer before crews can move on to the "bottom kill" -- the permanent fix for the well.

Thad Allen, the man in charge of the government response to the Gulf oil crisis, said Wednesday that the "fishing" operations had been delayed by a buildup of hydrates -- chemicals that form at low temperatures and high pressures toward the sea floor -- that temporarily jammed the cap that trapped oil in the well starting on July 15.

Crews, however, have now flushed the system to loosen the cap, thereby allowing them to begin "fishing" through the top of the well again.