The expression of biomass as a function of fishing effort at biological equilibrium
is the solution of the system
These insects are called biological control agents, play a crucial role in the reducing population density of phytphagous insects and balancing our biological equilibrium
In a sustained biological equilibrium (dX/dt = 0), equation (2) states that the off-take of the fleet is balanced by the growth of the stock.
In an unappropriated fishery, we find that the conditions defining a competitive equilibrium in each patch are identical to the single species setting except that the sustained biological equilibrium includes dispersal processes.
It is hereby proclaimed: All animals have equal rights to exist within the context of biological equilibrium
 have also defined a bioeconomic equilibrium model for "n" fishermen who catch three species; these species compete with each other for space or food; the natural growth of each species is modeled using a logistic law; the objective of their work is to calculate the fishing effort that maximizes the profit of each fisherman at biological equilibrium by using the generalized Nash equilibrium problem.
The biomasses at biological equilibrium are the solutions of the system
Thus, there is no biological equilibrium
when x > [lambda]/d.
However, when [R.sub.0] > 1, the disease-free equilibrium [E.sub.0] becomes unstable and there exists another biological equilibrium
, namely, chronic infection equilibrium [E.sub.1], that is globally asymptotically stable provided that condition (43) is satisfied.