OAKLAND (KRON) – A passenger on a San Francisco Bay ferry “is believed to have jumped” overboard into the Oakland Estuary on Sunday, according to a statement from the Water Emergency Transportation Authority.

“The captain was notified by witnesses and immediately turned the vessel around to initiate rescue procedures,” the statement reads. “First responders were contacted and took over the water rescue effort. The ferry crew remained on scene until local authorities arrived.”

The United States Coast Guard was called to the scene to attempt a rescue. The statement did not say if the person was found. When KRON4 reached out to the transportation authority, it referred the station to the Coast Guard.

Petty Officer Taylor Bacon told KRON4 that the Coast Guard became involved around 4 p.m. Sunday, after a 911 call was relayed from Oakland to the military branch.

The coast guard ended its search around 1 a.m. Monday without finding anyone, Bacon said. A spokesperson for the Oakland Fire Department told KRON4 that the person was not found as of midday Monday, and that local agencies had been on the water searching “until around midnight.”

Bacon said that there is a formula used by the Coast Guard to determine if it is reasonable someone survived in the water, and that once this formula shows there is no longer a reasonable possibility someone is alive, the search is called off.

There were disruptions and delays in service between San Francisco and Oakland and Alameda.

“Service to Main Street Alameda was suspended for about 90 minutes and resumed before 6 p.m.,” Thomas Hall of the transportation agency stated. “We experienced delays on the Oakland and Alameda the rest of the evening.”

“We will continue to assist first responders, including the U.S. Coast Guard, in the incident response and investigation,” the statement concludes.