WAILUKU, Maui — After a full month of testimony in a Maui courtroom, Hawai'i will learn today whether the Hawaii Superferry will be allowed to resume sailings between Honolulu and Kahului Harbor, a decision that likely will determine the fate of the new interisland transport.

A standing-room-only crowd of ferry employees, environmentalists, reporters and other observers listened to closing arguments yesterday but left disappointed after Circuit Judge Joseph Cardoza announced he needed one more day to consider the arguments and review newly filed documents.

He is expected to reveal his decision at 10 a.m. today.

The Sierra Club, Maui Tomorrow and the Kahului Harbor Coalition have asked the judge for a permanent injunction to keep the ferry docked while the state performs an environmental assessment of $40 million in ferry-related improvements at four harbors. Their concerns include increased traffic around ports, the potential spread of invasive species and collisions with humpback whales.

Hawaii Superferry President and CEO John Garibaldi has said such a ruling would essentially kill the company's plans for doing business in Hawai'i.

Attorneys for the company and the state Department of Transportation yesterday argued there is an overriding public interest in immediately relaunching the Hawaii Superferry's 350-foot, high-speed catamaran.

Hawaii Superferry attorney Lisa Munger said state law, the Legislature, the Lingle administration, the federal government and the state Public Utilities Commission all endorsed the ferry by approving financing, permits and other support. She listed those who appeared in court to testify in favor of the interisland service, including business people, civil defense officials and regular folks who were looking forward to the convenience of ferry travel.

She questioned the motives of ferry opponents, saying the request for an injunction had nothing to do with making sure environmental studies were conducted. "We're here today because the plaintiffs want to stop or punish the Hawaii Superferry while the Department of Transportation prepares an environmental assessment," Munger said.

Attorney Isaac Hall, representing the Sierra Club and the other two groups, said it was common sense and clear from the start that the ferry would have impacts on marine mammals, traffic, rural communities and invasive species.

He said the state Supreme Court issued an emphatic ruling Aug. 23 that struck down a DOT environmental exemption for the harbor improvements. Hall said the speedy ruling, issued the same day oral arguments were heard, showed the court wanted to give the plaintiffs time to seek a restraining order to halt the ferry before its scheduled launch date.

He said allowing the ferry to run while the assessment is conducted would violate state environmental laws and make it more difficult to impose operating conditions on the company, short-changing his clients' concerns.

Reach Christie Wilson at cwilson@honoluluadvertiser.com.