The Port of Long Beach handled about 20 percent less cargo in October than it did the same month last year, continuing a downward trend that started in July.

Port officials blame the drop in large part on the loss of a tenant, terminal operator California United Terminals, which moved from Long Beach to Los Angeles in December because a construction project would have disrupted its operations. That cargo terminal accounted for about 10 percent of the port’s cargo traffic, port spokesman Art Wong said.

Strong cargo growth in the first half the year masked the impact of CUT’s departure, but that the loss has been obvious for the past few months. Wong estimated that if CUT were still in Long Beach, October’s cargo traffic might have fallen like 10 percent.

Imports, the biggest segment of port traffic, were down 21 percent as retailers stocked up with fewer goods for the holiday shopping season.

“Orders this year are flat, but they’re saying in their retail reporting that they’re selling more than a year ago,” Wong said. “At some point, there’s going to be less on the shelves than there was a year ago.”