Hopf Bifurcation in a generalized food chain model with harvested on prey, predator or top predator population

A generalized prey-predator model with maturation delay is proposed. First harvest function on prey population is considered. Furthermore harvest functions on either predator or top predator population is considered. Conditions which guarantee the existence of Hopf bifurcation for every system are investigated. Local stability of the nontrivial positive equilibrium is analyzed