Description Usage Arguments Details Value References See Also Examples

Generate a starting value for `N`

, which represents the number of individuals in each length class for each species.

1 | ```
get_N0(nsc, nfish, mid, wgt, sc_Linf, intercept = 1e+10, slope = -5)
``` |

`nsc` |
A numeric value representing the number of length classes in the model. |

`nfish` |
A numeric value representing the number of fish species in the model. |

`mid` |
A numeric vector of length |

`wgt` |
A matrix with dimensions |

`sc_Linf` |
A numeric vector of length |

`intercept` |
A numeric value representing the number of individuals in the first length class. The default is |

`slope` |
A numeric value representing the slope of the community size spectrum. The default is -5. |

The total number of individuals in the community in each length class is equal to `intercept*mid^slope`

. Within each length class, the number of individuals of each species is determined using the proportion of each species' biomass that is found in that length class.

A matrix with dimensions `nsc`

and `nfish`

representing the number of individuals in each length class.

Andersen, K.H., Blanchard, J.L., Fulton, E.A., Gislason, H., Jacobsen, N.S., van Kooten, T. (2016). Assumptions behind size-based ecosystem models are realistic. *ICES Journal of Marine Science*, 73(6):1651-1655.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | ```
# Set up the inputs to the function
nfish <- nrow(NS_par)
nsc <- 32
maxsize <- max(NS_par$Linf)*1.01 # the biggest size is 1% bigger than the largest Linf
l_bound <- seq(0, maxsize, maxsize/nsc); l_bound <- l_bound[-length(l_bound)]
u_bound <- seq(maxsize/nsc, maxsize, maxsize/nsc)
mid <- l_bound+(u_bound-l_bound)/2
# Set up the inputs to the function - species-specific parameters
Linf <- NS_par$Linf # the von-Bertalanffy asymptotic length of each species (cm).
W_a <- NS_par$W_a # length-weight conversion parameter.
W_b <- NS_par$W_b # length-weight conversion parameter.
k <- NS_par$k # the von-Bertalnaffy growth parameter.
Lmat <- NS_par$Lmat # the length at which 50\% of individuals are mature (cm).
# Get phi_min
tmp <- calc_phi(k, Linf, nsc, nfish, u_bound, l_bound, calc_phi_min=FALSE,
phi_min=0.1) # fixed phi_min
phi_min <- tmp$phi_min
# Calculate growth increments
tmp <- calc_ration_growthfac(k, Linf, nsc, nfish, l_bound, u_bound, mid, W_a, W_b, phi_min)
sc_Linf <- tmp$sc_Linf
wgt <- tmp$wgt
# Get an initial population
get_N0(nsc, nfish, mid, wgt, sc_Linf)
``` |

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