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Table 1 Error rates of acoustic transmitter pressure sensor output associated with three external effects (i.e., water temperature, salinity, and atmospheric pressure)

From: Pressure sensor calibrations of acoustic telemetry transmitters

External effect Constant variables Range of external effect Estimated depth (m) Error (m) at a depth of 68 m compared to actual depth
Water temperature (°C) Salinity: fresh water ρ of 4 °C fresh water = 999.9720 kg/m3 67.88 0.12 shallower
Atmospheric pressure: standard ρ of 20 °C fresh water = 998.2072 kg/m3 68  
  ρ of 40 °C fresh water = 992.2164 kg/m3 68.41 0.41 deeper
Salinity (kg/m3) Water temperature: room temperature ρ of fresh water = 998.2072 kg/m3 68  
Atmospheric pressure: standard Salt water ρ = 1024.8103 kg/m3 66.23 1.77 shallower
Atmospheric pressure (Pa) Water temperature: room temperature Low P = 87,000 Pa 69.46 1.46 deeper
Salinity: fresh water Standard P = 101,325 Pa 68  
  High P = 108,000 Pa 67.32 0.68 shallower
  1. The estimated depths were calculated based on the hydrostatic pressure for fresh water at 20 °C and standard atmospheric pressure with the following formula: P total = P atmosphere + P fluid, (P fluid = ρgh), where ρ = water density (kg/m3), g = gravitational acceleration (9.8 m/s2), and h = depth (m). For all evaluations of external effects on depth estimates, depths of 68 m (maximum depth of V16 transmitters) were used because errors would be most pronounced here (i.e., because changes in water density are cumulative with depth)