Suppose that a predatory fish eats only minnows and the predator‒prey interaction follows Lotka‒Volterra dynamics. The intrinsic growth rate of minnows in the absence of predators is 0.2 per month, and the mortality rate of the predatory fish in the absence of minnows is 0.1 per month. The capture efficiency rate is 0.004, and the efficiency at which minnow biomass is converted into predator biomass is 0.25. The minnow population size will increase only if the number of predatory fish is
A) below 50.
B) equal to 50.
C) above 50
D) below 100.

Question

Quizplus · Accepted Answer

The minnow population will increase if the number of predatory fish is below the threshold where the predation rate equals the intrinsic growth rate. The threshold is calculated as the intrinsic growth rate (0.2) divided by the capture efficiency (0.004), which equals 50. Therefore, the minnow population will increase if the number of predatory fish is below 50.

Suppose That a Predatory Fish Eats Only Minnows and the Predator‒prey