Figures (1)  Tables (3)

    • Figure 1. 

      Length frequency of various trout species caught in gill nets at high mountain lakes in Idaho from 2001 to 2023. Sample size is given for each species.

    • Lake characteristic Mean SE Minimum Maximum
      Elevation (m) 2,396 24 1,338 3,165
      Lake size (ha) 4.15 0.28 0.16 22.87
      Shoreline development ratio 1.22 0.01 1.05 2.35
      Hiking distance (km) 7.8 0.4 0 25.4
      Cumulative elevation gain (m) 821 44 0 2,627
      Percent of hike on trail 76 2 0 100

      Table 1. 

      Characteristics of high mountain lakes in Idaho where trout were sampled with gill nets from 2001 to 2023.

    • Model AIC ΔAIC wi Adj r2
      Species + lithology + elevation + shoreline development ratio + net type + lake size + aspect + percent of hike on trail 62,697.62 0.00 0.99 0.18
      Species + lithology + elevation + shoreline development ratio + net type + lake size + aspect + cumulative hiking elevation gain 62,706.38 8.75 0.01 0.18
      Species + lithology + elevation + shoreline development ratio + net type + lake size+ aspect 62,711.12 13.49 < 0.01 0.18
      Species + lithology + elevation + shoreline development ratio + net type + lake size + aspect + hiking distance 62,712.30 14.67 < 0.01 0.18
      Null 64,041.34 1,343.72 < 0.01 −
      Plausible models were considered to be those with Akaike's information criterion (AIC) scores within 2.00 of the best model. Akaike weights (wi) were used to rank the relative plausibility of the candidate models, and adjusted coefficients of determination (r2) were used to assess the amount of variation explained by the models.

      Table 2. 

      Candidate general linear models relating lake characteristics to the size of trout captured with gill nets at high mountain lakes in Idaho from 2001 to 2023.

    • Parameter Estimate SE LCI UCI
      Intercept 270.522 8.561 253.742 287.302
      Net type - floating −0.234 2.249 −4.642 4.173
      Net type - unknown 9.731 2.329 5.165 14.297
      Lithology - acid volcanic −23.226 3.441 −29.970 −16.483
      Lithology - basalt −1.308 4.965 −11.039 8.422
      Lithology - sediment −15.146 3.059 −21.142 −9.150
      Lithology - shale −19.260 4.471 −28.024 −10.497
      Lake size (ha) 0.514 0.158 0.204 0.823
      Elevation (m) 0.015 0.002 0.010 0.019
      Shoreline development ratio −17.606 3.798 −25.051 −10.161
      Species - Brook trout −46.372 1.957 −50.207 −42.537
      Species - Cutthroat trout 9.571 2.035 5.582 13.560
      Species - Rainbow × Cutthroat hybrid −4.671 3.997 −12.505 3.163
      Aspect - lateral (i.e., E or W) −20.827 2.696 −26.112 −15.542
      Aspect - northern −13.373 2.326 −17.932 −8.814
      Percent of hike in trail −0.102 0.026 −0.153 −0.051
      Reference conditions for categorical variables were rainbow trout (for species), shield (for lithology), and sinking nets (for net type).

      Table 3. 

      Parameter estimates and lower (LCI) and upper (UCI) 95% confidence intervals for the most parsimonious general linear model relating lake characteristics to the size of trout captured with gill nets at high mountain lakes in Idaho from 2001 to 2023.