Loaded container volume at the Port of Oakland fell 12.7% in May compared to year-ago levels, port officials said Thursday, noting that the decline was expected due to the ongoing effects of Covid-19 on global shipping.

Officials cited lower consumer demand in domestic and foreign markets, both driven by coronavirus uncertainty, as the main reason for declining volume.

"Since March, the Port has seen indications of more significant cargo declines, so the May results are not unexpected," Port of Oakland Acting Maritime Director Delphine Prevost said in a statement Thursday. "Ocean carriers have been reducing the number of vessels in service in anticipation of expected declines in import demand. It's created challenges for exporters who are seeing less predictable vessel schedules and facing issues with finding capacity for their exports."

Loaded import volume fell 14.6% in May compared to year-ago levels while exports declined 10.7%. Total cargo volume for the month was down 16.8%, and year-to-date totals through May were down 7.8%, officials said.