Single-species size-spectrum simulator

This applet simulates the size distribution of a single species (blue) subjected to fishing (red). The filled area is the mature individuals and the colour whether recruitment is high (green) or low (red). The species is characterized by the asymptotic (maximum) size (W) and a set of non-dimensional parameters.

The model is based on metabolic scaling at the level of the individual. The full set of assumptions behind the model are documented in Andersen and Beyer (2013).


W = Asymptotic weight (g) (range: 1 g - 100.000 g)

a = Mortality (physiological level of predation) (range: 0 - 1)

ηm = Weight at maturity relative to the asymptotic weight (range: 0.1 - 0.9)

εa = Investment into activity as a fraction of available energy (range: 0.1 - 0.9)

Fishing selectivity type:


Ver. 1.2. Programmed by K.H. Andersen, Harsh Sahai and Alexandros Kokkalis. Rendered using flot and jQuery. Please mail comments and suggestions to