Slide show - Bull Trout

  • antenna arrays Stationary PIT (passive integrate transponder) tag antenna arrays were established at three sites in the Cedar River Municipal Watershed to evaluate fish movement. This photo shows the Boulder Creek site where antennas are arranged in a “pass-through” configuration.
  • thermoelectric generator The antenna arrays are powered by thermoelectric generators that run on propane (tank in trailer). These generators run in all weather conditions and the tanks are refilled once every two months. They provide a cost efficient means of running field equipment year round.
  • streambed secured antenna Some antennas are secured directly to the streambed, like these at the Cedar River site, and monitor fish moving across them. Data are recorded on a computer at the streambank and downloaded monthly.
  • crews sampling fish During the summer, crews sample select tributary streams of Chester Morse Lake and capture rainbow and bull trout.
  • typical fish habitat A variety of capture methods are used, including electrofishing and minnow trapping. Typical habitat where fish are located includes rootwads and small debris jams.
  • rainbow trout Rainbow trout (pictured) and bull trout are weighed prior to being implanted with a PIT tag. Each PIT tag has a unique 13 digit alpha numeric code that is read as fish move across stationary antenna arrays. The PIT tag never expires and remains in the fish for life.
  • bull trout Bull trout (pictured) and rainbow trout larger than 70 millimeters are PIT tagged prior to release at the point of capture.
  • tagging Fish are sedated and a tiny incision is made to insert the PIT tag. Fish recover in cold water before being returned to the stream.
  • pygmy whitefish Pygmy whitefish are also tagged during the late winter spawning migration. The PIT tags allow us to follow the frequency at which fish return to spawn.
  • adult bull trout As part of an acoustic tagging study of adult bull trout (pictured) and rainbow trout, we also insert PIT tags in each individual. Unlike the acoustic tags that expire within a few years, PIT tags remain active for the life of the fish, allowing researchers to understand spawning movements in the adult population.
  • tagging crew PIT tagging crews carefully record measurements of fish and keep updated records on fish distribution, size, and recapture history for many stream reaches in the upper watershed.
  • river The PIT tagging study allows SPU to evaluate movement of fish between rivers like the Cedar River and Chester Morse Lake. Data show the timing of movements and the size of the fish when they move between stream habitat and the lake.