newSingleSpeciesParams {mizer}

Set up parameters for a single species in a power-law background

Description

This functions creates a MizerParams object with a single species. This species is embedded in a fixed power-law community spectrum

N_c(w) = \kappa w^{-\lambda}

This community provides the food income for the species. Cannibalism is switched off. The predation mortality arises only from the predators in the power-law community and it is assumed that the predators in the community have the same feeding parameters as the foreground species. The function has many arguments, all of which have default values.

Usage

newSingleSpeciesParams(
  species_name = "Target species",
  w_max = 100,
  w_min = 0.001,
  eta = 10^(-0.6),
  w_mat = w_max * eta,
  no_w = log10(w_max/w_min) * 20 + 1,
  n = 3/4,
  p = n,
  lambda = 2.05,
  kappa = 0.005,
  alpha = 0.4,
  h = 30,
  beta = 100,
  sigma = 1.3,
  f0 = 0.6,
  fc = 0.25,
  ks = NA,
  gamma = NA,
  ext_mort_prop = 0,
  reproduction_level = 0,
  R_factor = deprecated(),
  w_inf = deprecated(),
  k_vb = deprecated()
)

Arguments

species_name

A string with a name for the species. Will be used in plot legends.

w_max

Maximum size of species

w_min

Egg size of species

eta

Ratio between maturity size w_mat and maximum size w_max. Default is 10^(-0.6), approximately 1/4. Ignored if w_mat is supplied explicitly.

w_mat

Maturity size of species. Default value is eta * w_max.

no_w

The number of size bins in the community spectrum. These bins will be equally spaced on a logarithmic scale. Default value is such that there are 20 bins for each factor of 10 in weight.

n

Scaling exponent of the maximum intake rate.

p

Scaling exponent of the standard metabolic rate. By default this is equal to the exponent n.

lambda

Exponent of the abundance power law.

kappa

Coefficient in abundance power law.

alpha

The assimilation efficiency.

h

Maximum food intake rate.

beta

Preferred predator prey mass ratio.

sigma

Width of prey size preference.

f0

Expected average feeding level. Used to set gamma, the coefficient in the search rate. Ignored if gamma is given explicitly.

fc

Critical feeding level. Used to determine ks if it is not given explicitly.

ks

Standard metabolism coefficient. If not provided, default will be calculated from critical feeding level argument fc.

gamma

Volumetric search rate. If not provided, default is determined by get_gamma_default() using the value of f0.

ext_mort_prop

The proportion of the total mortality that comes from external mortality, i.e., from sources not explicitly modelled. A number in the interval [0, 1).

reproduction_level

A number between 0 an 1 that determines the level of density dependence in reproduction, see setBevertonHolt().

R_factor

Use reproduction_level = 1 / R_factor instead.

w_inf

The argument has been renamed to w_max.

k_vb

The von Bertalanffy growth parameter.

Details

In addition to setting up the parameters, this function also sets up an initial condition that is close to steady state, under the assumption of no fishing.

Value

An object of type MizerParams

See Also

Other functions for setting up models: newCommunityParams(), newMultispeciesParams(), newTraitParams()

Examples

params <- newSingleSpeciesParams()
sim <- project(params, t_max = 5, effort = 0)
plotSpectra(sim)