Über die Beziehungen zwischen Länge, Umfang, Gewicht, Alter und Geschlechtsreife bei den Flußforellen des Rheins

Summary

Researches have been made on 141 river-trouts of the Rhine to find out some connection between length, size, weight, age and sexual maturity. Immature fish were only found among those whose bodies (without the tail-fin) were shorter than 25,5 cm (the full length being about 29 cm). Large specimens of fish show only a rather slight increase of weight. Only the females up to a length of 30 cm and only the males up to about 31 cm give a favourable utilization of the food. For the economical management of the trout-stock in the Rhine the width of net-meshes of 34 mm and the lowest length of catchable trouts of 28 cm, as appointed by law, seems to be effective and favourable.