Container traffic through the Port of Los Angeles slid more than 12 percent in June compared with a year ago when the economy began recovering from the recession.

The last month’s picture was brighter at the Port of Long Beach, where total container traffic was up 6.6 percent.

A total of 640,794 loaded or empty cargo containers were shipped out of the Los Angeles port last month, compared with the 730,317 containers moved through the port in 2010. Loaded inbound containers — an indicator of import activity — fell more than 10 percent last month, but loaded outbound containers rose a modest 5.5 percent.

“Given the early and exceptional 2010 summer surge, it’s not surprising that the June 2010 volumes aren’t exceeding 2010 volumes,” the port said in a statement.

The Long Beach port said import activity there rose 3.5 percent last month, much slower rate than the 27 percent improvement seen between June 2009 and 2010. Loaded outbound traffic was up 9 percent. The port handled 554,269 containers last month, compared with 520,100 in June 2010.

A nearly 30 decline in the number of empty containers being returned to Asia dragged down Los Angeles’ overall port activity. Returned empty containers at the Long Beach port were up more than 10 percent.