ARLINGTON – More than a dozen coho salmon gathered at the bottom of a sandstone waterfall on Prairie Creek on Friday, each mustering the energy to jump up on the 2-foot high rock bridge to thrash their way up its slippery surface into the safety of some watercress.

Time and again each massive fish tried and failed to make it over the natural barrier on the tributary to Portage Creek, the salmon-producing creek that runs through much of Arlington.

“I think it’s great – I haven’t seen (the salmon spawning) for many, many years,” said Mark Starwich of Stanwood, watching the fish spray water five feet into the air. “I feel like I should get down there and help them.”

Eventually the coho will make it on their own just fine, said Bill Blake, Arlington’s natural resources manager, pointing to tail-thrashing in the water upstream as proof that many make it past the tough spot.

However, the fish won’t make it if a group of kids that has been reportedly harassing coho on Portage Creek continue to chase, grab and toss them onto the stream’s banks, he said.

“If we don’t allow the fish to come in and lay their eggs, they’re not going to be able to come back,” Blake said. “Just because they’re in the middle of town, (the creek is) still a nursery.”

Salmon are struggling to survive in Snohomish County’s urbanized streams, so anything that makes it tougher for them to spawn is frowned on, said Doug Williams, a spokesman for the state Department of Fish and Wildlife.

“This is the critical time when coho salmon as well as chinook are spawning throughout the state,” he said. “Harassing them could cause them to abandon their reproduction. That’s why we want to keep folks out of streams this time of year.”

Pulling fish out of the water is an obvious no-no, he said. Less obvious is not walking in streams during spawning season.

“Walking up a stream can cause a great deal of harm to the eggs that are in the stream bed right now,” Williams said, explaining that the fish lay their eggs in gravel-bed nests called redds. “Someone stomping through a salmon redd has the potential to kill thousands and thousands of eggs.”

The penalties for harassing a fish range from a $100 misdemeanor to a $500 gross misdemeanor, Williams said.

“The rules guy says if the kid is throwing anything at the fish, shooting at it, using a gas or something else to poison it, trying to snag a fish, or stoning the fish, any of those activities carries a $500 fine and is considered a gross misdemeanor,” he said.

The penalties are stiff because the fish are in such dire danger of dying out in streams such as Portage Creek despite wildlife officials spending millions of dollars trying to help them come back, Williams said.

Fish numbers in Portage Creek have bounced back in recent years, but they’re not stable, Blake said.

“Ten years ago we were getting 50 to 60 fish in here,” Blake said.

Since then, efforts to remove barriers and improve habitat have caused those fish numbers to bounce back to a couple of hundred fish per year.

“We’d like to get it up to 800 to 1,000,” Blake said.

Reporter Lukas Velush: 425-339-3449 or lvelush@heraldnet.com.