Methods of calculating cohort production from field data‐some relationships

Four commonly used methods of directly computing cohort production are increment‐summation, removal‐summation, instantaneous growth, and the Allen curve. These may be used in either instantaneous exponential form or discrete linear form. The instantaneous exponential forms of the four methods are shown to be exactly equivalent. In discrete linear forms, the increment‐summation and removal‐summation methods are exactly equivalent, while the instantaneous growth and Allen curve methods are approximations of the other two. Simplified computational equations are given for calculating production by the various methods.