Ponderal production of<i>Tubifex tubifex</i>Müller and<i>Limnodrilus hoffmeisteri</i>Claparède (Oligochaeta, Tubificidae), benthic cohabitants of an artificial lake

Abstract

Abstract An attempt was made to estimate the main demographic parameters in two populations of the tubificids T. tubifex and L. hoffmeisteri. The eggs and worms were counted and the individual weights measured in adequate sub-samples. It was possible to subdivide each population into four groups: eggs and embryos (E), young (G1), young and regressed adults (G2), adults (A), so allowing the adoption of a four compartments model. The annual production of the two species was tentatively estimated.