The Board of Land and Natural Resources on Friday approved $633,840 in administrative fines and costs against a Hilo man who reportedly poisoned Paheehee Stream in north Hilo in order to harvest thousands of non-native prawns last year.

Officials indicated it’s unlikely Wayne Keaulana Spatz, 54, who has no known address, would be able to pay the penalties, but David Sakoda, a program manager with the state Division of Aquatic Resources, told board members, “I think a fine of that amount would make a statement and hopefully deter future incidents.”

The fine is the largest ever levied by the BLNR for an aquatic resource violation, according to the Department of Land and Natural Resources.

Troy Sakihara, an aquatic biologist with DAR, noted there recently were nine similar incidents involving streams in the same region, including one reported Thursday. “It’s still ongoing … ,” he said. “This is the only one that we’ve been able to identify a suspect.”

The DLNR has previously issued warnings to the public about eating freshwater Tahitian prawns without knowing where they came from, due to several cases in which pesticides were used in streams to collect the delicacy.

The case involving Spatz occurred July 13. When Hawaii County police officers and state Conservation and Resources Enforcement officer Edwin Shishido went to investigate a tip about the illegal activity, they spotted Spatz at the stream before he fled, according to a report to the BLNR submitted by DAR Administrator Brian Neilson.

A man who lives behind Paheehee Stream told officers he saw Spatz and a woman walking along the stream earlier in the day carrying three-prong spears, an opae net and bags. A few hours later, the witness saw dead and dying prawns floating down the stream and others scrambling out of the water.

Although prawns occasionally leave the water, a mass exodus such as in this case indicates the presence of an irritant or insufficient oxygen levels in the water, according to Sakihara.

The witness stated he filled at least seven 1-gallon bags with dead prawns before walking upstream about 100 yards from his residence to find Spatz with a bag — later determined to be a king-sized pillowcase — filled with the crustaceans, according to the report.

After returning to his house, the man observed a steady flow of dead and dying prawns floating downstream. Another resident posted photos and video on Facebook showing Spatz and the woman at the location.

The following day, Shishido returned to Paheehee Stream to take samples and noted a “creamy, yellowish” foam in the water, the report said. Later analysis of water and prawn samples found evidence of bifenthrin, a chemical used in pesticides to control ants.

The woman who was with Spatz at the time later told investigators that he liked to use Home Defense insecticide for collecting prawns. She was not cited in the case because officials said she did not participate directly in the poisoning.

Sakoda said that despite repeated attempts, officers were unable to contact Spatz to inform him of the impending BLNR action.

Based on Sakihara’s biological survey of the stream area, the poisoning is conservatively estimated to have impacted an area of 1,250 square meters and injured or killed 6,250 prawns, the report said.

The $625,200 fine includes a $200 penalty for “depositing a substance deleterious to aquatic life into state waters without a permit” and $100 per prawn. Added to that figure was $8,640 to compensate the state for the damage to natural resources on public lands and staff costs.

BLNR member Chris Yuen said the damage caused by the stream poisoning was “really quite severe. That’s a lot of prawns.” He suggested the department look into banning sale of stream-caught prawns since “you can’t collect enough legally to make it worthwhile to sell them … and because it’s hard to catch people.”

DLNR Chairwoman Suzanne Case called the use of toxins to harvest natural resources “appalling and extremely damaging to our natural resources where ever used.”

“Globally it’s understood to be a terrible method of collecting fish which is harmful not just to those fish and potentially to the humans who consume them, but very devastating to the native resources around them, and takes a long time to recover,” she said.

“We need to send a very strong message that this kind of illegal and extremely harmful fishing behavior — collecting prawns in streams using poison — is absolutely unacceptable and we will enforce it at every turn.”