SAN FRANCISCO -- After the tanker that leaked hundreds of gallons of fuel into the San Francisco Bay last week departed from San Francisco's Pier 80, crews continued to wind down their response to the spill on Friday.

A mechanical failure that occurred during a bunkering operation with a fuel barge Oct. 31 caused the Panamanian tanker Dubai Star to leak between 400 and 800 gallons of fuel into the Bay two miles south of the San Francisco-Oakland Bay Bridge.

The Dubai Star was taken to Pier 80 while authorities investigated the spill, but the vessel left for Martinez Thursday afternoon to unload its cargo, according to Lt. Andrew Kennedy.

Cleanup crews continue to work on controlling the damage caused by the spill, which has resulted in the deaths of 24 shorebirds and sent 37 others to an Oiled Wildlife Care Network treatment center in Fairfield.

By the end of Thursday, 8,900 feet of boom, a sponge-like material used to soak up the fuel, remained in the Bay compared to a total of 36,500 feet containing the spill last weekend.

More than 330 people were working on the cleanup during peak efforts on Sunday, but that number dropped to about 200 as of Thursday, according to the Coast Guard.

Crews continue to cleanup the shoreline at Robert Crown Memorial State Beach in Alameda, as well as in Ballena Bay and on Bay Farm Island.

On Friday, the East Bay Regional Park District reopened two of four closed shoreline areas that had been off limits due to the fuel spill.

Middle Harbor Shoreline Park in Oakland and Encinal Beach at Alameda Point in Alameda are open, according to district officials.

Robert Crown Memorial State Beach and the boat ramps at Martin Luther King Jr. Regional Shoreline Park in Oakland remain closed.