Table 1.
Parameters used to simulate hypothetical populations of channel catfish, lake trout, walleye, and white crappie.
The published sources of each parameter are included.
Table 2.
Gillnet selectivity functions for channel catfish, lake trout, walleye, and white crappie.
Selectivity functions and associated parameters for channel catfish, walleye, and white crappie were collected from Shoup and Ryswyk [14]. Selectivity functions and associated parameters for lake trout were collected from Hansen et al. [13]. The selectivity curves equations relate the mesh size j (mj) to the number of fish of length l capture in that mesh size. The remaining parameters are constants and are defined.
Fig 1.
Selectivity curves for channel catfish, lake trout, walleye, and white crappie.
The solid lines represent relative retention selectivity and the dotted lines represent retention and encounter selectivity. Note that x-axes have different scales.
Fig 2.
Box plots of total annual mortality estimates from simulated populations of channel catfish, lake trout, walleye, and white crappie.
Annual mortality was estimated using age data derived from simulations assuming 1) equal probability of capture, 2) capture based on retention probability, and 3) capture based on relative retention and encounter probabilities. Adjusted estimates represent age data that were corrected for relative retention probability or relative retention and encounter probabilities. The dashed lines represent the true annual mortality rate for each simulated population.
Fig 3.
Box plots of L infinity estimates from simulated populations of channel catfish, lake trout, walleye, and white crappie.
L infinity was estimated using length-at-age data derived from simulations assuming 1) equal probability of capture, 2) capture based on retention probability, and 3) capture based on relative retention and encounter probabilities. Adjusted estimates represent length-at-age data that were corrected for relative retention probability or relative retention and encounter probabilities. The dashed lines represent the true L infinity value for each simulated population.
Fig 4.
plots of von Bertalanffy growth coefficients from simulated populations of channel catfish, lake trout, walleye, and white crappie.
Box Growth coefficients were estimated using length-at-age data derived from simulations assuming 1) equal probability of capture, 2) capture based on retention probability, and 3) capture based on relative retention and encounter probabilities. Adjusted estimates represent length-at-age data that were corrected for relative retention probability or relative retention and encounter probabilities. The dashed lines represent the true growth coefficient for each simulated population.