[Increase functions of the type DW/DT = K(T + T0)P (E - W)N and their integrals (author's transl)]

In a series of systematical investigations into increase functions the type dW/dt = ktp (E - W)n and the resulting integrals with asymptotic growth for n = 1 and finite growth time for 0 less than n less than 1 were treated (Sager 1978). The growth function was tested for several species of fishes yielding good results generally but always implying horizontal tangent at the beginning for t = 0. This is of minor importance when the birth value W0 is only a small fraction of the final value E but becomes eventually intolerable when W0/E increases. In this case the increase function must be generalized to dW/dt = k(t + t0)p (E - W)n. The consequences of this step are followed up in this paper illustrated by graphs of the behaviour of the gained growth functions.