Ship congestion outside the busiest U.S. gateway for trade with Asia persisted over the past week as imports surged through March, usually one of the slower months of the year for container volumes.

A total of 25 container ships were anchored awaiting entry into the neighboring ports of Los Angeles and Long Beach, California, as of Sunday, compared with 28 a week earlier though still below a peak of 40 in early February, according to officials who monitor marine traffic in San Pedro Bay. Another 10 are scheduled to arrive over the next three days, with seven of those expected to drop anchor and join the queue.

The average wait for berth space was 8 days, unchanged from a week earlier, according to the L.A. port. That’s about triple the average delay in November.

Long Beach’s port last week said it handled the equivalent of 840,387 20-foot containers in March, topping the volume logged in December to become its busiest month on record.