Representation of a fish phase
Objects can be created by calls of the form
new("ref_stage", data="data.frame").
Object of class "data.frame" ~ The phases
available in the database
Object of class "data.frame" ~ The
phases available in the database
Other referential objects: charge,ref_choice-method,
  ref_checkbox-class,
  ref_choice-class,
  ref_coe-class, ref_dc-class,
  ref_df-class,
  ref_horodate-class,
  ref_list-class,
  ref_par-class,
  ref_parqual-class,
  ref_parquan-class,
  ref_period-class,
  ref_taxa-class,
  ref_year-class