Matson Navigation Co. is lowering its fuel surcharge for the second time in a row, representing a $100 to $150 reduction in shipping costs per container from the West Coast to Hawaii.

The state’s largest ocean shipper is cutting the fuel surcharge by 3.75 percentage points, to 21.75 percent from 25.5 percent, effective Sept. 12.

It is the lowest surcharge since June 2009, when the fee was 20 percent, and comes on the heels of a 2 percentage-point decline to 25.5 percent on July 18.

Besides a recent decline in bunker fuel prices, Matson operates a nine-ship fleet, down from a 10- to 11-ship fleet several years ago, resulting in container ships that are more than 90 percent full and thereby collectively burn less fuel, according to Matson spokesman Jeff Hull.

"We adjusted our fleet size to adapt to the economic downturn and that helps improve vessel utilization," he said.

Matson also said it is reducing its fuel surcharge for its Guam/Commonwealth of the Northern Mariana Islands and Micronesia service by 3.75 percentage points, to 23.25 percent from 27 percent, on the same day.

Representatives of Horizon Lines didn’t respond to calls for comment, but Hawaii’s second-largest ocean shipper typically matches Matson’s surcharge adjustments.

Pasha Hawaii Transport Lines, which carries vehicles between Honolulu and San Diego, likely will match Matson’s decrease early next week, according to General Manager Reggie Maldonado.

Overall oil prices have been falling since April due to concerns that the United States’ economic recovery appears to be slowing, according to economist Carl Bonham, executive director of the University of Hawaii Economic Research Organization.

"Price movements associated with energy costs have been a big piece of overall Honolulu inflation," he said.

"In a nutshell, the declining surcharge is obviously a good thing because it helps to hold down the price of everything we purchase."