Find the current biomass at which it would take HZN mean generation times to reach Bfrac x SSBMSY biomass level given zero catches
getBlow(x, N, Asize, SSBMSY, SSBpR, MPA, SSB0, nareas, retA, MGThorizon, Find,
Perr, M_ageArray, hs, Mat_age, Wt_age, R0a, V, nyears, maxage, mov, Spat_targ,
SRrel, aR, bR, Bfrac = 0.5, maxF, ploty = F)position in a vector
array of numbers at age by sim and area (dims nsim, maxage, nyears, nareas)
matrix of area size (nsim by nareas)
vector nsim long of spawning biomass at MSY
matrix nsim by nareas with SSB per recruit
matrix nyears + proyears by nareas of spatial closures
vector of SSB0 length nsim
numeric. number of areas
array of retention nsim x maxage x nyears
vector nsim long of MGT x HZN
matrix of fishing mortality rate nsim x nyears
matrix of recruitment devitions nsim x nyears + maxage -1
array of natural mortality rate nsim x maxage x nyears + proyears
vector nsim long of steepness values
array nsim x nages x nyears+proyears of maturity at age
matrix nsim x nages of weight at age
matrix nsim by nareas of unfished recruitment
array of vulnerability nsim x maxage x nyears
integer: number of historical years
integer: maximum age
array of movement nsim x 2 x 2
vector of spatial targetting parameters
integer representing recruitmetn dynamics type 1: Bev Holt 2: Ricker
vector of recruitment parameters
vector of recruitment parameters
fraction of SSBMSY that is the target
maximum apical fishing mortality
logical: should a plot be produced