Plot natural mortality
plot_natural_mortality(
  M,
  plt_knots = TRUE,
  knots = c(1976, 1980, 1985, 1994),
  slab = "Knot"
)list object created by read_admb function
if the knots should be plotted or not
(nuveric vector), specifies the knots.
the x-axis label for the plot
plot of natural mortality