Most calculations of fish growth from scale measurements are made from one of four types of curves: straight line through the origin (Dahl-Lea); straight line with intercept (Lee); logarithmic line (Monastyrsky); empirically derived curve (SegerstråYle). Occasionally, different curves are used for different length intervals of fish. Present understanding of the basic principles of research on the body-scale relation is good but certain problems still await clear solution.
Nomographic devices for the calculation of growth appeared early. Many of these unnecessarily had a moving part. The simplest nomograph yet developed and one that can be adapted to any kind of body-scale relation was described by Carlander and Smith. Computers appear to be destined to replace nomographs in most large-scale research on growth.