ASHLAND — Tiny Hamilton Creek snaking down from the hills above Ashland to hug the northbound lanes of Interstate 5 has state fish biologists wide-eyed over how even the smallest of urban streams can play key roles in wild salmon survival.
In the summer, Hamilton Creek's flows into Bear Creek are so thin that an errant hubcap tumbling down the freeway bank could easily block it.
"Most of the year, it's only a foot wide," says biologist Chuck Fustish from the Oregon Department of Fish and Wildlife. "Definitely not fish-worthy."
But its stature has risen since Fustish discovered that Hamilton Creek truly became a comfort for infant wild coho salmon and steelhead seeking refuge from recent storms.
A fish trap placed three weeks ago in this seemingly good-for-nothing creek has regularly captured steelhead and coho, a threatened species, that are escaping the roil of Bear Creek during storms.
It's the latest urban stream within the Rogue River basin where Fustish has discovered a winter role in aiding wild salmon production despite the stream's generally poor condition most days.
"These tributaries that don't appear to be worthy of fish in the summer have their importance," Fustish says.
Fustish is in the third year of a five-year study meant to map fish use in urban streams of the upper Rogue River basin, particularly those within the Bear Creek drainage surrounded by urban development.
Wire-mesh "hoop" traps are placed strategically in the streams to capture all fish that migrate up the creek before and during high-water events.
Juvenile salmon and steelhead can spend up to two years in fresh water before heading to the ocean, where they put on most of their poundage before returning as adults.
In the Bear Creek basin, the trapping has shown that the juveniles move around in search of usable habitat at different times.
The study has shown that even the most neglected urban streams can be short-term refuges from high and muddy flows in Bear Creek during storms.
In other winters, the trapping has produced hundreds of young salmon in places such as Lazy Creek in Medford's Bear Creek Park as well as Larson Creek, which passes through much of Medford's southeast development area.
"They have to go someplace, and this is where they're going," Fustish says.
This winter, Fustish has placed traps in Hamilton Creek, Lazy Creek, Military Slough in the White City Industrial Area and in Gore Creek, a short stream that flows under the South Pacific Highway near an adult book store before dropping into Bear Creek.
Jeremy Stahler, a Southern Oregon University biology major, has volunteered to check the Hamilton Creek trap each weekday.
"We put the trap in and the next day there were fish in it," says Stahler, 22, of Central Point. "Pretty amazing."
Stahler identifies and measures each fish before releasing them upstream of the trap. He clears it of debris and replaces it in the stream as semitrailers rush by a stone's throw away.
Fustish says Hamilton Creek perhaps is the smallest of the sample streams where fish have been caught for his study.
"That's probably one of the last little streams we'd expect to see fish in," Fustish says. "It shows we're still learning what kind of habitat juvenile fish use in the wintertime.
"About anything that has water in it, it seems fish can use," he says.
Reach reporter Mark Freeman at 776-4470, or e-mail firstname.lastname@example.org.