Figure 3. The George River subpopulation tracked carrying capacity (K)
throughout its population cycle. Maximum and minimum rates of annual
(intrinsic+ immigration) population growth (λmax =
2.848; λmin = 0.345) were greater than the biological
maximum annual intrinsic population growth rate (λmax =
1.363; Heard, 1980) during the eruption phase. The eruption period (λ
> 1.0 and increasing over consecutive years or λ
>1.20) lasted for approximately 9-years. When
λt values were ≥1.2 we limited them to 1.2 for
calculation of the associated Verhulst (1838) determination of
Kt because the Verhulst logistic equation is specific
for intrinsic λ only (no immigration). We choose λ ≥ 1.2 as the
threshold because natural subpopulations experience some natural and
harvest mortality; and because not every reproductive age female
produces viable offspring in every year. Nt closely
tracked Kt throughout the cycle with the maximum lag
time over one complete cycle (1965-2017) being
4.334-years.