Annual selectivity shifts are also provided for. These allow selectivities to shift to the left or
right with changes in an exogenous variable. (In the 2002 hoki assessment, this exogenous
variable is either related to the depth being fished or the time of the fishing season, see
Francis et al. 2003.) The ogive is shifted by a f E f E f , where a f is a shift factor and E f is
the exogenous variable. This is accomplished by changing the parameters of the ogive, for
example, in a logistic ogive, the a 50 parameter is shifted.
Temperature influences availability...
For example, plucked from the CASAL user manual:
Annual selectivity shifts are also provided for. These allow selectivities to shift to the left or right with changes in an exogenous variable. (In the 2002 hoki assessment, this exogenous variable is either related to the depth being fished or the time of the fishing season, see Francis et al. 2003.) The ogive is shifted by a f E f E f , where a f is a shift factor and E f is the exogenous variable. This is accomplished by changing the parameters of the ogive, for example, in a logistic ogive, the a 50 parameter is shifted.