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Natural mortality at age

Source: R/natural-mortality.R
get_M.Rd

Constructs a vector of natural mortality (M) at age values using a declining early-age curve and late-age increase.

Usage

get_M(
  min_age = 0L,
  max_age = 30L,
  age_increase_M = 25L,
  m0 = 0.4,
  m4 = 0.1,
  m10 = 0.1,
  m30 = 0.4
)

Arguments

min_age

Numeric scalar. Minimum model age.

max_age

Numeric scalar. Maximum model age.

age_increase_M

Numeric scalar. Age at which M begins to increase again.

m0

Numeric scalar. Natural mortality rate at model ages 0 and 1.

m4

Numeric scalar. Natural mortality rate at age 4, used to determine the slope of the early-age decline.

m10

Numeric scalar. Natural mortality rate at age 10 and throughout the subsequent flat section.

m30

Numeric scalar. Natural mortality rate at the terminal model age.

Value

A numeric vector containing natural mortality rates in increasing age order.

Details

This RTMB helper implements the SBT assessment's 0–30 age-grid parameterization. Its early-age assignments and control points are tied to that grid; changing min_age, max_age, or the age layout requires corresponding implementation changes rather than merely passing different argument values.