One of the state's largest illegal industries took a hit over the weekend after a Kaua'i family was arrested and charged with growing nearly 6,000 marijuana plants worth more than $5 million on state land, law enforcement officials said.

"What made it stand out was the sheer volume of the operation. It is my understanding that this amount makes this the largest outdoor marijuana growing operation ever prosecuted in the state of Hawai'i," U.S. attorney Ed Kubo said yesterday. "This haul was very sizable and substantial and this will have an impact (on the local industry)."

While overall marijuana activity decreased from 2004 to 2006, the latest year for which figures are available, the state remains the fourth-largest producer of marijuana in the country, according to the Office of National Drug Control Policy.

Law enforcement officials say the latest seizure, of 5,922 marijuana plants worth $5.9 million from the base of Mount Wai'ale'ale on Friday, will put a dent in production.

California, Kentucky, and Tennessee annually lead the nation in marijuana production, although Hawai'i pot is by far the most potent, according to the national drug control office, with THC levels topping 15 percent, and is among the most sought-after strains in the world. THC is the chemical responsible for marijuana's narcotic effect.

By comparison, Kentucky "ditch weed" has a potency between 3 percent and 5 percent.

"Your grandfather's doobie from the 1960s has become a dangerous drug," said Larry Burnett, director of the Hawai'i High Intensity Drug Trafficking Area, a coalition of state and federal law enforcement agencies that operates the most widespread narcotic intelligence network in the Pacific and targets the largest drug-trafficking organizations operating in Hawai'i.

The marijuana growing season in Hawai'i runs from March to November, and more than 830,000 marijuana plants have been seized in Hawai'i since 2004, according to the national drug control policy office.

The problem peaked in the 1980s, and 1.9 million plants were recovered in 1987. Authorities credit aggressive enforcement for a reduction in the marijuana cultivation.

Arrested on Kaua'i Friday were Edward H. Holland, 55; Mark Steven Darling, 52; Robert Jason Bihm, 28; Melissa Ann Bihm, 27; and Ryan Edward Bihm, 23.

Holland is the father of Robert and Ryan Bihm. Melissa Ann Bihm is Robert Bihm's wife. Darling is a friend and roommate of Holland's.

All but Holland face between 10 years and life in prison if convicted. But because of a prior federal drug conviction, Holland faces between 20 years and life in prison.

He was arrested and convicted in 1991 with possessing with intent to distribute 97 pounds of marijuana and using the U.S. mail to sell his supply. He served four years in federal prison.

Six vehicles were seized as part of the ongoing operation and officials are working to determine who the group was supplying and where the money went.

"The Holland organization is no more and we will continue to identify other members of this organization and take every penny they earned illegally," said Anthony D. Williams, assistant special agent in charge of the U.S. Drug Enforcement Administration's Honolulu district office.

"Operation Green Stream" was launched in November after a Kaua'i Police Department aerial surveillance team, acting on a tip, discovered two separate growing areas in a rural, rugged area about an hour's hike from the end of Kuamo'o Road.

The road is only accessible by four-wheel drive vehicles and the marijuana plots are on a hillside near a waterfall, authorities said.

Kaua'i police officers and federal agents had to hike and wade for an hour along a "circuitous stream for some distance," according to a criminal complaint filed in U.S. District Court.

After observing the areas by air, a team hiked to the location and found evidence of an elaborate operation, including more than 200 plastic "grow bags," remnants of harvested marijuana plants, shovels, soil sifters and other gardening tools.

Law enforcement officers set up two surveillance posts in March and chronicled the activities of the Bihm family as they planted, nurtured and harvested marijuana from April until Friday, according to court documents.

On Aug. 13, surveillance cameras recorded Holland inspecting the plants, "sometimes putting on his eyeglasses to examine the plants more closely," and spreading fertilizer around the plants, according to court documents.

Melissa and Robert Bihm were videotaped filling grow bags with dirt and picking mature buds from plants, according to court records.

At one point, Melissa Bihm was observed "rolling a marijuana joint and then lighting it up. She then shared this joint with her husband, Robert," the records say.

Officers also tracked and recorded the vehicle trips taken by Darling and the Bihms from their homes to the rural grow area.

All five defendants made preliminary appearances in federal court yesterday afternoon.

Magistrate Judge Leslie E. Kobayashi told them the government has filed a motion to detain all without bail because of the seriousness of the charges and because they are flight risks and pose a danger to the community.

That motion will be argued at hearings scheduled for tomorrow and Friday.

Agents with the U.S. Drug Enforcement Administration, Internal Revenue Service, Immigration and Customs Enforcement, the state Department of Land and Natural Resources, the Kaua'i Police Department, the FBI, the Hawai'i Army National Guard, state deputy sheriffs and the U.S. Coast Guard investigated the case.

Reach Peter Boylan at pboylan@honoluluadvertiser.com.