WAILUKU, Maui — The manager of the state Plant Quarantine Branch yesterday testified the Hawaii Superferry is "a new but negligible pathway" for the spread of fire ants, coqui frogs and other pests.

Carol Okada said the interisland ferry will transport a relatively small volume of passengers, vehicles and cargo compared to other maritime carriers. Combined with customers' ready compliance with screening procedures during its first voyages, that makes the vessel a "very low risk" for spreading invasive species, she said.

Okada was testifying in a Maui Circuit Court hearing to determine whether the company should be allowed to resume service while the state conducts an environmental assessment of ferry-related projects at Kahului Harbor. A day after launching service Aug. 26 between Honolulu, Kaua'i and Maui, the ferry was halted by a Maui court order and protests on Kaua'i.

Twenty alien species are introduced into Hawai'i each year, with four or five developing into serious pest problems, according to Okada. The pests, which result in crop damage, market losses and control costs totalling hundreds of millions of dollars, will continue to spread throughout the Islands with or without Hawaii Superferry, she said.

"It will continue to move as it's doing now. It's just a matter of time ... ," she said. "As long as people move and cargo moves, invasive species will move."

The Sierra Club, Maui Tomorrow and the Kahului Harbor Coalition have cited concerns about the spread of invasive species as one reason to keep the 350-foot catamaran tied up at the dock while ways to reduce the threat are examined as part of the court-ordered environmental assessment.

The groups claim the ferry will make it much more convenient for campers, hikers and hunters to take their cars, trucks and gear into wilderness areas where they can pick up seeds, insects and other pests.

The ferry is expected to carry an average of 400 passengers and 110 vehicles per trip. The Department of Agriculture was approached by the company in 2005 to discuss the invasive species issue and develop training for company employees in screening procedures.

As required of all interisland carriers, plants or plant parts are not allowed on board without a certificate of inspection from the Department of Agriculture. Cut flowers and produce do not need certificates, but are subject to random agricultural inspection.

The ferry also is not allowing the transport of soil, and boot brushes are available at the check-in to remove mud and dirt from passengers' footwear.

Although not required by state rules, ferry workers visually screen vehicles and passengers and look under the hood and in the trunk of each car and inside coolers. If plants are spotted, the workers will check for inspection certificates.

The ferry employees will not conduct agricultural inspections, Okada said, because that is the duty of the state agency. "We don't expect the Superferry to be able to detect pests or disease on a plant," she said. "That is our job."

The company will turn away vehicles covered with excess dirt or caked mud. Hawaii Superferry official Lani Olds testified Thursday that she is talking with car wash companies and service stations about setting up an arrangement where ferry customers can get a fare discount if they show up at the pier with a just-washed vehicle.

Okada said state agricultural inspectors will be monitoring the ferry screenings for a month before evaluating the effectiveness of the procedures.

Teya Penniman, head of the Maui Invasive Species Committee, last week testified the Hawaii Superferry could be doing more to keep invasive species from hitchhiking on vehicles.

She said a committee advising the company on vehicle-screening procedures recommended a high-pressure undercarriage wash to flush seeds and other tiny material from hard-to-reach spots. Other recommendations included vacuuming vehicle interiors; hot-water treatment of plants to remove frogs, stinging nettle caterpillars and other pests; bleach baths for fishing nets to kill algae and other material; and a canine team to sniff out smuggled plants and animals.

No other air or sea carriers in Hawai'i employ such measures.

Penniman also said she didn't feel the company allots enough time for thorough vehicle screening, considering the ferry's quick turnaround at ports. On Maui, the vessel is scheduled to arrive from Honolulu at 9:30 a.m. and leave at 11 a.m.

Okada said an undercarriage wash might have some value, but it's likely not cost-effective and would not be asked of high-volume carriers such as Young Brothers or Matson.

Also appearing in court yesterday was Greg Kaufman of the Pacific Whale Foundation, who has expressed concerns about collisions between humpback whales and the high-speed ferry. His testimony will continue when the hearing reconvenes at 9 a.m. Monday.

Still waiting to testify are John Garibaldi, Hawaii Superferry president and chief executive officer, and Barry Fukunaga, head of the state Department of Transportation.

Reach Christie Wilson at cwilson@honoluluadvertiser.com.