Description
An operating model component that specifies the parameters of the population
dynamics modelSlots
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)
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)
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)
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 form which parameters were taken to define the operating model
Objects from the Class
Objects can be created by calls of the form
new('Stock', OM)