The state gave Pasha Hawaii Transport Lines LLC the go-ahead yesterday to begin an interisland shipping business that will challenge Young Bros. Ltd.’s decades-old regulated monopoly.

The Public Utilities Commission authorized Pasha to operate between Honolulu, Kahului, Hilo, Nawiliwili, Barbers Point and Pearl Harbor through Dec. 31, 2013. The commission will then evaluate the effects of the service and make a final decision on the company’s request to operate in the market permanently.

Young Bros. argued that Pasha will only serve the biggest ports and the most lucrative lines such as autos, heavy equipment and construction materials. Young Bros. also said that Pasha will "cherry-pick" the most lucrative routes and could harm local farmers and cattle ranchers who receive discounts subsidized by higher rates on other goods.

The PUC said it determined there was no evidence yet that Pasha’s service would harm the public or Young Bros.

"Pasha’s proposed intrastate operations will foster competition in the intrastate shipping industry and provide consumers with a choice of intrastate water carriers," the PUC said in a news release. A second carrier could help in case of service disruption, the PUC said.

Young Bros., a division of Seattle-based Saltchuk Resources Inc., operates 12 weekly shipments to neighbor island ports and subsidizes rates to smaller ports such as Molokai and Lanai with more profitable shipments between larger ports.

California-based Pasha has provided West Coast-to-Hawaii shipping service since 2005, using its 579-foot ship the Jean Anne. Pasha filed an application with the PUC in March 2009 to use the Jean Anne to make interisland trips every two weeks.