| Objective | Criteria | Rationale |
---|---|---|---|
1 | Detect changes in trajectory | Mean error ≤1.77 m | Many trajectory based analyses are only preserved when the average position error is <10% of the mean step length [17]. Transmission delay was (33.4 s), sea lamprey ground speed is 0.53 ms-1 [18, 19], equating to a step length of 17.7 m. |
2 | Assign behavioral state (moving or stationary) to fish positions | Max error <15Â m | Simple behavioral assignment of moving or stationary with first passage time analysis, which is a measure of the time it takes an individual to leave a circle of fixed radius r drawn around each measured location to determine if movement is occurring [20, 21]. Based on prior analyses, a displacement of greater than 15Â m per transmission at the average tag transmission rate (33.4Â s) could result in a false designation of moving when the fish was stationary. |
3 | Assign habitat to fish positions | 2DRMS ≤6 m | To ensure accurate assignment of each estimated fish position to habitat types that are defined at the resolution of 18 × 18 m grid cells we selected a twice the distance root mean square (2DRMS) error of <6 m for our selected HPE values. |
4 | Balance loss of acceptable data and retention of unacceptable data | Retain 95% of acceptable data, Reject ≥99% of unacceptable data | To ensure accurate assignment of each estimated fish position to habitat types while avoiding loss of accurate data. We aimed to keep 95% of acceptable data (≤6 m) while retaining <1% of unacceptable data (>6 m) of all retained positions (unacceptable data remaining/all retained positions × 100). |