# Calculate the proportion of mature individuals Calculates the proportion of individuals that are mature for each species and length class. ```r calc_mature(Lmat, nfish, mid, kappa, sc_Linf, eps = 1e-05, force_mature = TRUE) ``` ## Arguments - `Lmat`: A numeric vector of length `nfish` representing the length at which 50% of individuals are mature for each species. - `nfish`: A numeric value representing the number of species in the model. - `mid`: A numeric vector of length `nfish` representing the mid-point of the length classes in the model. - `kappa`: A numeric vector of length `nfish` representing the rate of change from immaturity to maturity for each species. - `sc_Linf`: A numeric vector of length `nsc` representing the length class at which each species reaches its asymptotic length. - `eps`: A numeric value specifying a numerical offset. The default is `1e-5`. - `force_mature`: A logical statement indicating whether to force all fish in the largest length class to be mature. The default is `TRUE`. ## Returns A matrix with dimensions `nsc` and `nfish` and elements in the range 0-1 representing the proportion of individuals that are mature for each species and length class. ## Details The proportion of individuals in the `j`th length class of the `i`th species that are mature is described by a logistic model `1/(1+exp(-kappa[i]*(mid[j]-Lmat[i])))` ## Examples ```r # Set up the inputs to the function - species-independent parameters 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 <- tmp$phi phi_min <- tmp$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 mature <- calc_mature(Lmat, nfish, mid, kappa=rep(10, nfish), sc_Linf) ``` ## References Hall, S. J., Collie, J. S., Duplisea, D. E., Jennings, S., Bravington, M., & Link, J. (2006). A length-based multispecies model for evaluating community responses to fishing. **Canadian Journal of Fisheries and Aquatic Sciences**, 63(6):1344-1359.

calc_mature function