this is like a little fish m.a.s.h. unit.fish biologists have to tag them so they can be tracked. >> we're going to make a small incision on the left side of the fish. >> reporter: first, you have to knock them out. >> we have to knock them out with alka-seltzer gold. they kind of go to sleep for a little bit. >> reporter: time to go sideways. >> that's a good sign. >> reporter: they are getting sleepy. then, the tiny fish head to the miniature operating table. >> we measure him. he's going to be 59 millimeters. we take the tag and slide it into the incision. >> reporter: how rewarding it is it? >> it's very rewarding. to have a job where you know you're making a difference. and in the long-term, can keep this population alive. >> that's about all she's going to need. >> reporter: the salmon rescue operation involves many different players. including local landowners, many of the threatened fish have ended up on their property. where we're walking is normally underwater. >> yes. >> reporter: what does it tell you about the sh