Ships are resuming weekly calls at the Port of Oakland this week, a sign that the effects of the West Coast port slowdown are beginning to subside, port officials said yesterday.

"Some vessels that were omitting Oakland have already started to return, and a look at schedules indicates that the rest will be back soon," said Port of Oakland Maritime Director John Driscoll. "This tells us that shipping lines are confident we're recovering from the recent logjam."

The news follows similar word from other regional ports that are struggling to shrink their container backlogs. The Port of Long Beach announced April 1 that it planned to resume normal operations within four to six weeks.

Operations at 29 West Coast ports affected by the months-long contract impasse between the International Longshore and Warehouse Union (ILWU) and the Pacific Maritime Association (PMA) began the road to normalcy on Feb. 20 after both sides agreed to a tentative five-year contract. As expected, the first month or so was difficult. Overwhelmed ports worked beyond their usual full capacity to clear out the backlogs that had accumulated during the impasse and alleged work slowdown by the ILWU. Meanwhile, loaded cargo vessels idled in the Pacific Ocean waiting to offload cargo.

In an effort to work around the blockage, some shipping lines avoided the overwhelmed ports and sought out uncongested destinations. Despite their efforts, many frustrated clients felt the effects. At the ProMat 2015 trade show in Chicago, one company missed an opportunity to unveil its latest material handling crane because the product was stranded on a ship off the West Coast.

In Oakland alone, more than two dozen vessels bypassed the port during January and February to try their luck elsewhere or return to home ports, contributing to a 31.6-percent decline in container volume at the port in those months.

Now those ships are adding Oakland back to their list of active ports. Returning services so far include the container carriers Maersk of Denmark and MSC of Geneva, as well as two services controlled by the G6 Asian/European alliance, port officials said. The G6 group will restore its remaining two lines later in April, and the Asian CKYHE group is expected back by early May.