The Chironomus tentans Survival and Growth Bioassay: A Study of the Effect of Reduced Larval Growth Upon the Following Generation and an Application of the Bioassay in Evaluating Sediment Quality

Abstract

A life-cycle study was conducted with Chironomus tentans to assess the significance of growth retardation of second to third instar larvae over a 10-d test period on long-term survival, emergence success, and fecundity. Larval growth was controlled by using six feeding levels ranging from 0.2 to 5.9 mg dry weight Tetrafin® fish food per day. Growth of second generation larvae was correlated with maternal growth in additional experiments. Mean 10-d growth (Y) of second to third instar C. tentans larvae displayed a strong linear relationship with measured feeding level (X) best described by the equation: Y = -0.16 + 0.20X (r2 = 0.99). Growth at the six feeding levels were all statistically different (p < 0.05), yet mean 10-d survival was 88% in all cases.