The production of larval Chironomidae in the mud at Loch Leven, Kinross

The production of four dominant species of larval Chironomidae (Chironomus anthracinus. Glyptotendipes paripes. Polypedilum nubeculosum and Limnochironomus pulsus) was measured and compared between different sections of the mud zone covering a total area of 662 ha (50 per cent of the loch bed) from March 1971 to March 1972. The results showed that the performance of Chironomus was very similar throughout the area in respect to numbers, growth and production but it was more variable in other species. The mean annual dry weight production of Chironomus over the whole area was 26 g/m2 and the four species together raised this to 29 g/m2 (equivalent to 579 k J/m2). The numbers of Chironomus increased and Glyptotendipes decreased through the sampling period. Estimates of biomass are given for other larval Chironomidae present in the mud. The accuracy of the results is discussed. as well as the variations in the seasonal growth of larvae and the changing composition of the community; some tentative estimates are given of assimilation by larval Chironomidae. The methods used for analysing these data are described in an appendix.