The Port of Long Beach reported a nearly 21 percent spike in traffic for November despite a strike that slowed operations the last few days of the month.

A total of 555,513 containers moved through the port last month, according to figures released Thursday, with imports up more than 20 percent, and exports rising more than 24 percent compared with the same month a year earlier. The number of empty cargo containers shipped out of the port rose more than 18 percent.

Port officials attribute the uptick in activity to major container shipping carriers, such as CMA CGM and MSC, increasing their stops at the port in recent months.

After mostly declining traffic in the middle of the year, the late boost helped bring cumulative port cargo volumes closer to last year’s levels. For the first 11 months of this year, imports are down 0.3 percent, but exports are up 2 percent.

Port clerks launched an eight-day strike at the Port of Los Angeles on Nov. 27, with the job action spreading to the Long Beach the following day. The strike shuttered most terminals at the Port of Los Angeles, but only three of Long Beach’s six terminals were affected. The Los Angeles port is expected to release its November figures Friday.