DLMtool (version 4.4.1)

Stock-class: Class 'Stock'

Description

An operating model component that specifies the parameters of the population dynamics model

Slots

Name

The name of the Stock object

maxage

The maximum age of individuals that is simulated (there is no 'plus group': individuals die off beyone the maximum age so there isn't a huge cost to simulating more older age classes)

R0

The magnitude of unfished recruitment. This is normally fixed to some arbitrary value since it simply scales the simulated numbers)

M

Natural mortality rate (uniform distribution)

M2

Optional vector of M-at-age (must be length maxage)

Msd

Inter-annual variability in natural mortality rate expressed as a coefficient of variation (uniform distribution)

Mgrad

Mean temporal trend in natural mortality rate, expressed as a percentage change in M per year (uniform distribution)

Mexp

Exponent of the Lorenzen function assuming an inverse relationship between M and weight (uniform distribution)

Fdisc

Fraction of discarded fish that die

h

Steepness of the stock recruit relationship (uniform distribution)

SRrel

Type of stock-recruit relationship (1)Beverton-Holt (2) Ricker

Linf

Maximum length (uniform distribution)

K

von B. growth parameter k (uniform distribution)

t0

von B. theoretical age at length zero (uniform distribution)

LenCV

Coefficient of variation of length-at-age (assumed constant for all age classes (uniform distribution)

Ksd

Inter-annual variability in growth parameter k (uniform distribution)

Kgrad

Mean temporal trend in growth parameter k, expressed as a percentage change in k per year (uniform distribution)

Linfsd

Inter-annual variability in maximum length - uniform distribution

Linfgrad

Mean temporal trend in maximum length, expressed as a percentage change in Linf per year (uniform distribution)

recgrad

Mean temporal trend in log-normal recruitment deviations (uniform distribution)

AC

Autocorrelation in recruitment deviations rec(t)=AC*rec(t-1)+(1-AC)*sigma(t) (uniform distribution)

a

Length-weight parameter alpha (uniform distribution)

b

Length-weight parameter beta (uniform distribution)

L50

Length-at- 50 percent maturity (uniform distribution)

L50_95

Length increment from 50 percent to 95 percent maturity

D

Current level of stock depletion (Bcurrent/Bunfished) (uniform distribution)

Perr

Process error, the CV of lognormal recruitment deviations (uniform distribution)

Period

Period for cylical recruitment pattern in years (uniform distribution). Leave empty to ignore

Amplitude

Amplitude in deviation from long-term average recruitment during recruitment cycle, both positive and negative (uniform distribution). E.g., a range from 0 to 0.5 means recruitment decreases or increases by up to 50% each cycle. Leave empty to ignore

Size_area_1

The size of area 1 relative to area 2 (uniform distribution)

Frac_area_1

The fraction of the unfished biomass in stock 1 (uniform distribution)

Prob_staying

The probability of inviduals in area 1 remaining in area 1 over the course of one year

Source

A reference to a website or article from which parameters were taken to define the operating model

Objects from the Class

Objects can be created by calls of the form new('Stock')

Examples

# NOT RUN {
showClass('Stock')

# }