The life‐cycle and productivity of Tibifex tubifex (Oligochaeta; Tibificidae) in the Moat‐Feeder Stream, Cardiff, South Wales

Abstract

A population of Tubifex tubifex in an organically rich stream was found to have an annual life‐cycle with a prolonged period of reproductive activity throughout the winter and spring. Cocoons were produced mainly during the late winter and early spring. No cocoons were found during August and September, and there were few mature worms at this time. The population density ranged between 5420 m −2 in mid‐September and 613000 m −2 in mid‐May. The maximum population biomass (Bmax) recorded was 106 g dry wt m −2 (March) and the minimum was 10 g dry wt m −2 (September). Total annual production (P) was 139 g dry wt m −2 and the average annual biomass ( B ) was 46 g dry wt m −2 giving an annual P/ B ratio of 3.0, and a P/Bmax ratio of 1.3.