LOGISTIC.BISECTION.K: LOGISTIC BISECTION

In antarctic-humpback-2019-assessment/HumpbackSIR: Use Sample-Importance-Resampling to Estimate Southern Humpback Abundance

LOGISTIC BISECTION

Description

Method of Butterworth and Punt (1995) where the prior distribution of the current absolute abundance $N_2005$ and maximum net recruitment rate r_max are sampled and then used to determine the unique value of the population abundance $N$ in start_yr (assumed to correspond to carrying capacity $K$). Requires TARGET.K and subsequent dependencies.

Usage

LOGISTIC.BISECTION.K(K.low, K.high, r_max, z, num_Yrs, start_yr,
  target.Pop, catches, MVP, tol = 0.001)

Arguments

K.low	Lower bound for $K$ when preforming the bisection method of Punt and Butterworth (1995). Default is 1.
K.high	Upper bound for $K$ when preforming the bisection method of Punt and Butterworth (1995). Default is 500,000.
r_max	The maximum net recruitment rate ($r_max$).
z	The parameter that determines the population size where productivity is maximum (assumed to be 2.39 by the IWC SC).
num_Yrs	The number of projection years. Set as the last year in the catch or abundance series, whichever is most recent, minus the start_yr.
start_yr	The first year of the projection (assumed to be the first year in the catch series).
target.Pop	A sample of the prior on population abundance $N$, in numbers, set as sample.N.obs sampled from priors$N.obs
catches	The time series of catch in numbers or biomass. Currently does not handle NAs and zeros will have to input a priori for years in which there were no catches.
MVP	The minimum viable population size in numbers or biomass. Computed as 3 * num.haplotypes to compute minimum viable population (from Jackson et al., 2006 and IWC, 2007).
tol	The desired accuracy (convergence tolerance) of stats::uniroot.

Value

A numeric scalar of an estimate of carrying capacity $K$.

Examples

LOGISTIC.BISECTION.K(K.low = 1, K.high = 100000, r_max = r_max, z = z,
                     num_Yrs = bisection.Yrs, start_yr = start_yr,
                     target.Pop = target.Pop, catches = catches, MVP = MVP,
                     tol = 0.001)

antarctic-humpback-2019-assessment/HumpbackSIR documentation built on Nov. 6, 2023, 6:07 p.m.