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Table 2 Number, size and tag burdens of subyearling and yearling Chinook salmon tagged with either a PIT tag or with a PIT tag and an acoustic tag (AT Fish) and released at Lower Granite Dam across three years

From: Survival of seaward-migrating PIT and acoustic-tagged juvenile Chinook salmon in the Snake and Columbia Rivers: an evaluation of length-specific tagging effects

   Sample size   
Stock Year PIT AT Fork length range (mm) Median (range) AT tag burden (%)
Yearling 2006 19,111 898 120–149 3.2 (2.2–5.0)
  2007 49,167 3,755 110–159 3.6 (2.0–7.4)
  2008 53,592 4,087 100–159 2.3 (1.2–7.4)
Subyearlinga 2007 35,793 9,760 80–129 6.3 (2.5–15.1)
  1. aSurvival estimates from release to LMN were not produced for subyearling Chinook salmon ranging in fork length from 80 mm to 89 mm or 120 mm to 129 mm due to low PIT detection probabilities for these length-classes, causing unreliable estimates. Sample sizes to LMN were thus 32,904 (PIT) and 8,641 (AT).
  2. AT acoustic transmitter, PIT passive integrated transponder.
  3. Fork length indicates the range of fish sizes included in the analysis for a given year and stock. Tag burdens were calculated as weight of fish/weight of tag (PIT + AT tag weights).