PRED.GROWTH.RATE: PREDICTED GROWTH RATE

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

PREDICTED GROWTH RATE

Description

PRED.GROWTH.RATE computes the predicted growth rate if such information is available from an independent estimate rather than being estimated from data. Growth rate is calculated as: $$r_t_0 - t_fin^pred = \frac \sum_t = t_0 ^t_fin - 1 ln \left( \fracN_t+1^pred N_t^pred \right) t_fin - t_0 = \frac ln \left( N_fin^pred \right) - ln \left( N_0^pred \right) t_fin - t_0 $$ where $N^pred$ is the model predicted population size, in numbers, at time $t$ or $t+1$ in years, $t_0$ is the start year of the equation (1995 in Zerbini et al. 2011), and $t_fin$ is the last year of the equation (1998 in Zerbini et al. 2011).

Usage

PRED.GROWTH.RATE(growth.rate.Yrs, Pred_N, start_yr = start_yr)

Arguments

growth.rate.Yrs	The years to be used for growth rate computation. 1995 - 1998 are used in Zerbini et al. 2011.
Pred_N	Time series of predicted abundance, in numbers, from GENERALIZED_LOGISTIC.
start_yr	The first year of the projection (assumed to be the first year in the catch series).

Value

A numeric scalar representing predicted growth rate.

Examples

growth.rate.Yrs  <-  c(1995:1998)
Pred_N <- c(1000, 1500, 1500, 2000)
start_yr  <-  1995
PRED.GROWTH.RATE(growth.rate.Yrs, Pred_N, start_yr=start_yr)

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