YAKIMA, Wash. — The most popular stretch of the Yakima River spring chinook fishery — the final 3,500 river feet downstream from the railroad bridge below Roza Dam — is also its most precarious.

If anglers aren’t on their best behavior, they could lose it.

There’s a reason as much as 80 percent of the entire Yakima River sport harvest will take place around the river’s final hairpin curve below the railroad bridge: That’s where the salmon will stack up, seemingly as thick as sardines in a can, before they begin heading up the dam’s fish ladders.

Which is why anglers will be lining those banks starting this Saturday, when the Yakima River opens to spring chinook fishing from the Interstate 82 bridge at Union Gap to the railroad bridge below Roza.

To get one of those highly-prized bank spots, though, anglers must either cross private property on their way to the east bank or cross the dam to reach the west bank. And either the private landowner or the Bureau of Reclamation — or, for that matter, the BNSF Railway, whose tracks many of those anglers routinely cross — could put the kibosh on the entire process.

“We’re at the mercy of a private landowner and a federal agency,” said John Easterbrooks, the Washington Department of Fish and Wildlife’s regional fish program director.

“If either one of those goes south on us, we’re in trouble.”

Officially, this year’s Yakima River springer fishery has already been open for a week and a half. But that 45-mile stretch of meandering river between Richland and Prosser was never the main event for anglers, even though nearly 1,000 springers — nearly 300 of them of hatchery origin, eligible for anglers’ dinner tables — have already navigated its distance.

It’s already been eight days since the first adult springer made it through Roza, and others won’t be far behind. So come Saturday, hosts of anglers will be heading for that hairpin river curve, which stretches from the deep, cliff-lined “Glory Hole” below the bend to the railroad bridge just above it.

And Easterbrooks is adamant that those anglers remember that fishing there “is a privilege, not a right.”

It’s a privilege that has often been abused.

Last year, the WDFW brought in extra garbage bins and portable toilets next to the parking area just up from the dam and at the roadside parking area atop Roza Cut. Before that, some anglers would simply dump their garbage at the roadside before driving away or, worse, would relieve themselves right there next to their cars — not a pleasant sight for the family from whose home those anglers were in plain sight.

“Those guys ruin it for the people doing it right,” said Eric Stein of Yakima, an avid chinook angler who regularly fishes the hairpin curve during springer season. “It only takes a couple of people who don’t want to pack all their garbage back out and just leave it there. It can be very gross.”

Stein said he believed the situation improved last year “because people know they could lose it,” but that there are “still the knuckleheads” who park at the top of Roza Cut and don’t bother to use either the dumpster or the portable toilet the WDFW is providing there for the duration of the fishery. Most do clean up and haul out their own messes, Stein said.

“It has gotten better,” he said. “It’s not perfect. It’s not fixed. But it’s gotten better, and I don’t want it taken away just because people can’t clean up after themselves.”

Some anglers will fish the river in drift boats, between Harrison Road and Harlan Landing or from Harlan to Union Gap. Some will run a jet sled up to Wenas Creek, but they’ll have to bank the boat to fish that productive hole because fishing from a motorized boat is strictly prohibited upriver from Selah Gap, even from the back of a banked boat.

Others will bank-fish along the latter stretch, casting their baited hooks below a slip bobber from spots where they won’t have to endure the nearly elbow-to-elbow angling — what some call “combat fishing” — that can occur in the last stretch below Roza.

The potential for angler friction was eased with the ban on fishing from motorized boats. That rule change was for partly for safety reasons, to miminize the possibility of a jet sled whipping around a sharp bend and hitting a drift boat or a wading bank angler.

But another reason was to prevent the type of conflict between anglers that nearly erupted in recent years when one or two fishing guides motored up to the railroad bridge and anchored in the middle of the river, right between all those bank anglers.

“So the guys fishing from the shore would get (their lines) hung up on this guy’s anchor line. They’re losing gear; they’re not happy,” Easterbrooks said. “And then (the guides) would have somebody else running clients in and out, so they never had to move. They could stay there all day.

“That’s the main reason the rule got changed, because it was going to get unruly. There was going to be bloodshed.”

Those boats won’t be anchored in that oh-so-popular hole under the railroad bridge, thanks to the new rule, but bank anglers will still have their own guidelines to follow. Those using the dam to access the west bank must follow the route signs posted on the dam and along the west-bank path. It’s illegal to cross the tracks or the trailroad bridge, in either case an offense subject to a criminal trespassing charge and as much as a $500 fine.

BNSF spokesman Gus Melonas said the railroad route passing through the Yakima River Canyon averages 10 to 12 trains daily, and that two of Washington’s 20 railroad trespass fatalities in 2013 came on that route.

“Trains can be on any track at any time,” Melonas said, “in any direction. We do typically see an increase (in track-trespass fatalities) around this time of year around the waterways, and BNSF will be monitoring around the clock.”

Daily limit for the Yakima River fishery is two hatchery chinook (identified by a clipped adipose fin, some 3,350 adults of which are expected to return to the Yakima River this year. Another 5,760 wild/natural origin chinook, including 1,590 headed for the Naches and American rivers, make up the bulk of this year’s 9,110 total run estimate.