Read up on r-selected species and k-selected species
K = carrying capacity, and k-selected species are typically long-lived larger species that take longer to reach sexual maturity, have fewer offspring, and will typically have some sort of parental care (perennial plants, sea turtles, elephants, humans, etc.)
r-selected species reach sexual maturity fast, produce lots of offspring, do not live long, and typically don't spend too much energy on parental care (annual plants, mice, bacteria, etc.)
I would think trout fall more into the r-selected species they don't take long to reach sexual maturity, they are prolific spawners, and they just deposit their eggs and leave. Think of k as quality and r as quantity, and when you try to start managing for quality in an r-selected species in the wild, it usually doesn't pan out. Crappie and bluegill would fit this category as well. Just think of trout and panfish as mice, farmers (fishermen) spend millions each year trying to control (catch) the mouse populatioon, and yet with all that expensive chemicals and mouse traps (baits), the population keeps on coming back because they are resilient. Now if you want to try and grow bigger mice (trout) then you need to start taking away some of the smaller ones so the larger ones will have less competition from the smaller mice (trout).
