SAN FRANCISCO, California (CNN) -- Federal investigators have launched a criminal probe into a cargo ship collision and oil spill, the Coast Guard said, which killed hundreds of birds in San Francisco Bay.

The container ship MV Cosco Busan hit the San Francisco-Oakland Bay Bridge Wednesday and is being held in Oakland for repairs, said Adm. Thad Allen, the commandant of the Coast Guard on Sunday night.

Although the captain and crew were not allowed to leave the vessel due to federal shipping laws, they were not officially detained, said Coast Guard spokeswoman Anastasia Belvin.

Allen had told reporters Sunday that no restrictions had been placed on the crew.

Twenty wildlife teams are expected to search the bay Monday for birds sickened by the an estimated 58,000 gallons of heavy-duty bunker oil that oozed into the water after the collision, said a Department of Fish and Games official. Watch Allen on the criminal probe »

The Cosco Busan was departing Oakland for South Korea in dense fog when it hit a tower supporting the western suspension span of the Bay Bridge, the Coast Guard said. After the accident, the ship moored near Treasure Island, which the bridge crosses.

The spilled oil formed globules along the San Francisco city waterfront and out of San Francisco Bay, beneath the Golden Gate Bridge toward Marin County.

Seven miles of containment equipment stretched across the bay has collected 12,271 gallons of oil so far, while another 4,000 gallons has evaporated, officials said. See where oil spilled »

The 902-foot container ship has a 212-foot-long, 12-foot-wide gash in its side that allowed the oil to leak from partially filled fuel tanks, according to National Transportation Safety Board spokeswoman Debbie Hersman.

The NTSB is reviewing the ship's voyage data recorder, which should have recorded captain and crew conversations on the bridge and other information in the 12 hours leading up to the bridge collision, Hersman said.

Nearly 200 dead birds have been recovered from the bay, while another 465 birds have been rescued alive but oiled, according to Lisa Curtis, administrator of Department of Fish and Games office of spill prevention and response. See photos of oil coating the bay »

The crew was new to the ship, which was built six years ago in South Korea but purchased just last month by the current owner, Hersman said. They were on their first voyage in the vessel, she said.

The U.S. attorney in San Francisco opened a criminal investigation over the weekend to see if federal maritime laws may have been violated by the captain and crew, Allen said. "The vessel is detained in port under a captain of the port order because it is unsafe to sail."

Several beaches and shorelines were closed to the public and fishing was banned in certain locations on Port of San Francisco property.

"This an incident which, in my view, should not have happened," Sen. Dianne Feinstein, D-California, said Sunday after being briefed by Coast Guard officials.

Rear Adm. Craig E. Bone, the Coast Guard's director of inspection and compliance, echoed Feinstein's comments.

"There's systems, there's capabilities, there's licensed operators, there's a pilot on board the vessel, there's the capacity and the capability to safely navigate through this port and waterways every day," he said.

He added, "But we have to move beyond the incident and the fact that it occurred and move forward into the response."

On Friday, Gov. Arnold Schwarzenegger declared a state of emergency, freeing money to clean up the spill.

Some lawmakers -- including the state's other U.S. senator, Democrat Barbara Boxer, and Maine Republican Sen. Olympia Snowe -- initially criticized the Coast Guard's handling of the collision and resulting spill.

"I am deeply concerned about the recent news reports that the Coast Guard had underestimated the severity of the spill and after learning of the spill's true size failed to report that information for more than four hours," Snowe said in a statement Saturday.

Snowe is the ranking member of the Senate's Subcommittee on Oceans, Atmosphere, Fisheries and the Coast Guard.

"I am very troubled by the Coast Guard's delay in delivering accurate information to the public and to the city of San Francisco," Boxer wrote Thursday in a letter to Allen.

The Coast Guard initially reported that the ship's owner had said only 140 gallons had spilled from the Cosco Busan, Boxer said.

Feinstein touched on the criticism Sunday. "There's room for improvement, obviously," in how the accident and spill were handled, she said. But she acknowledged that fog had hindered initial aerial reviews of the accident site.

On Saturday, the National Transportation Safety Board announced it was sending a team to San Francisco to investigate the accident.

"If there are people responsible or accountable for the causal factors of this, they'll be held accountable," Bone said.

The California Department of Transportation said the collision did no structural damage to the bridge and there was no interruption of bridge traffic -- more than 250,000 vehicles daily. E-mail to a friend

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