In advance of finalizing the details of the Northwest Seaport Alliance at a joint meeting Aug. 4, the ports of Seattle and Tacoma began to report joint cargo statistics.

The latest numbers show that cargo volume at the two ports jumped 14 percent in June year-over-year.

Last October, the two Puget Sound ports announced the formation of the Northwest Seaport Alliance this year to unify the management of the two ports’ marine cargo terminals and related functions under a single umbrella.

Through the first half of the year, volumes remained stable with the Washington state gateway handling nearly 1.8 million TEUs (20-foot container units), a three percent gain year-to-date.

Containerized exports rose five percent on the year through June to 628,718 TEUs, while imports grew nearly three percent to 715,307 TEUs. Domestic volumes remained flat, up one percent year to date to 433,715 TEUs.

Empty container exports were up 86 percent year-to-date, as excess equipment that accumulated during the West Coast dockworker contract negotiations was sent back to Asia, the two ports said.

Other cargo categories were variable. Auto import volumes increased by five percent to 93,890 vehicles, while break-bulk cargo fell by two percent in the first half and grain exports dropped by eight percent.

The Northwest Seaport Alliance, called an “unprecedented level of cooperation between the state’s two largest container ports, “is a strategic response to the competitive pressures that are reshaping the global shipping industry. Where we were once rivals, we now intend to be partners,” said Stephanie Bowman, co-president of the Port of Seattle Commission.

When the new alliance was announced, Port of Tacoma Commission president Clare Petrich, said, the two ports “form the third-largest container gateway in North America, “face fierce competition from ports throughout North America, as shipping lines form alliances, share space on ever-larger vessels and call at consolidated terminals at fewer ports.”

With the ports working in unison, she added, “We can better focus on financially sustainable business models that support customer success and ensure our ability to reinvest in terminal assets and infrastructure.”