SALEM â Next to the babbling banks of the Santiam Riverâs south fork, Brooke Penaluna sought a flat spot to set up shop. She plopped down a black, pipe-like reservoir with four clear cups on top and clicked the power button on a small pump that sounded like the worldâs tiniest lawnmower. âAnd then we put on our gloves and our waders, and we go out into the stream,â said Penaluna, who works as a research fish biologist for the U.S. Forest Serviceâs Pacific Northwest Research Station. Near the middle of the river, Penaluna carefully dipped four plastic bottles into the oncoming water, tightly capping them for the journey back to shore.