PHOENIX — For years, Jim Ferguson and other volunteers have used a special fish trap, water bucket and a simple aquarium fishnet to survey for wild steelhead captured in the Bear Creek Basin's urban tributaries.
Ferguson would pull them out of the trap with the net and place them in the bucket to be identified, counted and released.
This year, however, he's added a pair of scissors to expand that survey one little snip of a fin at a time.
Ferguson and others are adding a new twist to a simple juvenile steelhead survey by clipping a tiny piece of the tail fin of the fish caught in these traps. That way, when and where these young fish get captured again in another survey trap will add a new chapter to the unfolding story of the basin's urban streams.
Years of trapping juveniles as they move in and out of tributaries during the winter have shown young steelhead rely on even the smallest seasonal streams as refuges from Bear Creek in high-water events.
But the fin-clipping is the first step in learning how steelhead hide out in the same creeks all winter, whether they move around and, if so, how far they go. It could show whether Medford fish ever head up to Ashland streams to cool off in the summer. Over time it could also estimate how many steelhead are in individual creeks during each storm and how long they stay.
"We've been doing this trapping for years and now we're adding a new component to it," says Ryan Battleson, an Oregon Department of Fish and Wildlife biologist overseeing the survey. "We mark the fish and see if we catch it again.
"This is the simplest way of doing a mark and recapture," Battleson says. "For a species like this, it's hard to get your arms around them without it."
The ODFW biologists and volunteers began building and installing these portable "hoop" traps in 2005 to do simple surveys of what fish species are present in 34 Rogue Basin streams, including 11 Bear Creek tributaries. Not only did the traps capture young steelhead everywhere the traps were placed, biologists found fish in five streams previously deemed fishless.
The data shows that even the shortest, seemingly innocuous tributaries at times provide key refuges for wild steelhead.
So far, however, Battleson and a few volunteers have kept this winter's surveys to Wagner Creek and this unnamed seasonal stream through Phoenix's Blue Heron Park where young steelhead were only recently found.
They have captured and fin-clipped 34 steelhead in the stream, and recaptured seven of them again as they used the tributary during a later freshet.
In Wagner Creek, 36 steelhead have been fin-clipped, and six of them have been recaptured, Battleson says.
Ultimately Battleson would like to institute a broader survey by trapping and tagging young steelhead in several Bear Creek tributaries, each of which would be color-coded to denote where they were originally captured.
Eventually he'd like to see the survey taken digital by fitting some young steelhead with transmitters so their movements could be tracked in real time. That could provide bushels of information to reveal how complex and far-reaching the usable habitat is in these urban streams for these iconic fish.
"I think Bear Creek would be perfect for that," Battleson says. "It's a very urban stream. We certainly can study it a lot better."