SBR was significantly affected by the level of copper exposure and larval size but not by timing of exposure (Table 3.4b). Level of copper exposure accounted for most of the variation explained by the model after heterogeneity across containers (random term), with a conditional R2 of 25% for the full model. However, only settlers from the High copper level were significantly different from controls, with spines an average of 49% ± 10 of body size against 40% ± 12 of body size in controls(Coefficients contrasts: t = 5.10, p < 0.001). Larvae from jars in which average body size was large at the end of the larval stage tended to produce settlers with larger spines relative to their body size (Figure 3.2b).