This animation is a plan view (down from above) of the model stream. Habitat cells are shaded by depth- brighter cells are deeper. Flow is from right to left through this riffle-pool-riffle sequence. The blue line segments are individual adult trout, and segment length represents trout size (except for graphics resolution errors). Fish in each cell are displayed from top to bottom in order of decreasing length.
The simulation is initialized with 10 trout of nonuniform size. Five initial time steps occur, then on successive time steps the largest remaining trout is (a) tagged (turned yellow), then (b) removed from the simulation, until only one trout remains. The animation automatically replays when finished.
In this EM simulation, the most
preferred cell is the deepest one, which offers highest survival probability
and food intake sufficient to minimize starvation risk. The largest trout always
occupy this preferred cell. Competition for food causes smaller trout to select
nearby cells that offer suboptimal but good combinations of survival and food
intake. As the largest trout are successively removed, the hierarchy shifts
as remaining fish move into the preferred cell.