project               package:FLAssess               R Documentation

_p_r_o_j_e_c_t_i_o_n _m_e_t_h_o_d _f_o_r _F_L_S_t_o_c_k _o_b_j_e_c_t_s

_D_e_s_c_r_i_p_t_i_o_n:

     A method for projecting FLStock objects.

_U_s_a_g_e:

     project(stock, control, sr)

_M_e_t_h_o_d _a_r_g_u_m_e_n_t_s:


     '_s_t_o_c_k'   : an object of class FLStock or of one that inherits
          from it.

     '_c_o_n_t_r_o_l' : an object of class projectControl specifying the
          forcast parameters.

     '_s_r'      : an object of class FLSR giving the stock recruit
          relationship.

_D_e_t_a_i_l_s:

     project conducts a deterministic projection on an FLStock object
     for which estimates of population abundance and harvest at age
     have been determined. The project method provides a simplified,
     pure R, version of the fwd method. The syntax and arguments to
     project are similar to those of fwd, however, only the basic
     functionality of the stock projection process is provided. Users
     wishing to perform more complex multi-fleet, multi-stock, area or
     sex disaggregated projections or to project objects other than
     FLStock objects should use the fwd method available from the FLash
     package.

     The project method has three arguments. An FLStock object for
     which estimates of population abundance and harvest at age are
     available and to which the stf method has been applied (the stf
     method extends the FLStock object to the required number of years
     and fills a number of slots with the appropriate values ready for
     the projection). The control object specifies the target values in
     each year for the projection. These can be any combination of
     catch, landings, ssb or fishing mortality targets. Finally the
     method requires an FLSR object that will specify the value of
     future recruitments.  

     In the example provided below a 5 year projection is conducted for
     the period 2009 to 2013. An SSB target is specified for the first
     year. Note that an SSB target specified for 2009 will determine
     the exploitation level in 2009 that will provide the target SSB at
     spawning time the following year. Consequently the resulting
     FLStock object has an SSB of 250000 t in 2010. The catch, landings
     and f targets all take effect in the year for which they are
     specified, ie. catch in 2010 is 80000 t, landings in 2011 are
     60000 t and so on. Note also that the f targets correspond to the
     fbar value such that fbar in 2012 and 2013 are 0.4 and 0.5
     respectively.

_A_u_t_h_o_r(_s):

     Rob Scott

_S_e_e _A_l_s_o:

     projectControl, stf

_E_x_a_m_p_l_e_s:

     data(ple4)
     ple4.stf <- stf(ple4, 5)
     ple4.sr  <- sr(as.FLSR(ple4,model=geomean))
     ctrl     <- projectControl(data.frame(year=2002:2006, 
                                           val=c(250000, 80000, 60000, 0.4, 0.5), 
                                           quantity=c('ssb','catch','landings','f','f')))
     res      <- project(ple4.stf, ctrl, ple4.sr)

