n_to_stock {optistock}

Calculate the number of fish to stock based on desired recruit number and given mortality curve

Description

This function is essentially the inverse of recruits_at_time. Given the number of fish desired at a certain time and the mortality function and parameters this function will calculate how many fish should be stocked into a system.

Usage

n_to_stock(
  time_at_stocking,
  time_at_rec,
  n_recruits_desired,
  mort_fun = exp_mort,
  mort_fun_args
)

Arguments

time_at_stocking

The time that fish are stocked (i.e. synonymous with the amount of time that fish are raised in a hatchery)

time_at_rec

The time at which a fish enters the fishery (i.e. the amount of time it takes a fish to grow to a desired length). Use inv_vb to calculate this.

n_recruits_desired

The number of recruits desired at time_at_rec

mort_fun

The mortality function, see ?mort_funs

mort_fun_args

List. Named arguments to be passed to mort_fun

Value

The number of fish to be stocked at time_at_stocking to get the desired number of fish at time_at_rec based on the mortality function and associated parameters

Examples

# how many fish to stock on day 100 if you want 10000 fish on day 1000
n_to_stock(10000, 100, 1000,
           mort_fun = exp_mort,
           mort_fun_args = list(m_init = (1 / 365),
                                m_inf = (0.2/365),
                                alpha = 0.005))