SAVANNAH, Ga. — Bigger ships arriving through an expanded Panama Canal pushed cargo volumes at Georgia’s seaports to record levels in fiscal 2017, the Georgia Ports Authority announced Monday.

The state agency reports its ports in Savannah and Brunswick handled 33.4 million tons (30.3 million metric tons) of total imports and exports in the fiscal year that ended June 30. That’s the ports’ greatest tonnage ever and an increase of 8.3 percent over the previous year.

Griff Lynch, the port authority’s executive director, said the growth came almost entirely from the Port of Savannah’s booming trade in containers — giant metal boxes used to ship retail goods from consumer electronics to frozen chickens. Savannah is the nation’s fourth-busiest container port, behind only the ports of New York-New Jersey, Los Angeles and Long Beach, California.

Savannah moved a record 3.85 million container units, up 6.7 percent from fiscal 2016. It was only three years ago that Savannah reached a milestone 3 million container units for the first time, and Lynch said it’s feasible the port could pass 4 million containers next year.

The big numbers come after the Panama Canal finished a major expansion last summer, making room for the two largest cargo ships ever to call on the East Coast to make stops in Savannah in May and June.

“The canal has been probably the largest single game-changer we’ve seen this year,” Lynch said.

The record surge in containers at Savannah offset a down year at the Port of Brunswick, Lynch said, where bulk cargo lagged all year and automobile shipments were essentially flat.

The last time Georgia’s ports saw a peak year was 2015, when growth was fueled by labor woes on the West Coast that caused shippers to reroute cargo to Savannah and other East Coast ports. Lynch said the boom at Georgia ports this past year resulted from “organic growth” rather than any one-time occurrence that forced a shift in shipping schedules.

“Hopefully this is sustainable for the long term,” Lynch said.

Port officials are planning ahead. The Georgia Ports Authority board Monday approved nearly $73 million to buy six more ship-to-shore cranes to arrive at Savannah’s docks in 2020. By that time, Lynch said, Savannah will have 36 total cranes — half of which will be tall enough to load and unload supersized ships.

That will enable the Port of Savannah to work on three giant ships simultaneously, he said.

A $973 million project to deepen the Savannah River shipping channel so the big ships can travel the waterway fully loaded even at low tides is scheduled for completion in 2022.