4.3.1.3 Delayed development
There was evidence of delayed development, with the proportion of plutei with a rudiment and competent plutei (protruding rudiment) decreasing with increasing copper level, especially in the Water treatment (Table 4.5a and b, Figure 4.3). In the Water treatment, only 4% of larvae were competent in the ANZECC Chronic treatment and none in the High Chronic treatment, compared with 39% in the controls(Coefficient contrasts; in all cases p < 0.01). There was no difference across all treatments with respect to the proportion of 8-armed plutei in late larval development(Two-way ANOVA; Source: F(2, 24) = 2.7, p = 0.09, Copper level: F(3, 24) = 0.12, p =0.95, Interaction: F(6, 24) = 1.4, p = 0.27).
Table 4.5: Two-way ANOVA of Evechinus chloroticus proportion of larvae with a rudiment (A) and
proportion of larvae with a large rudiment with protruding spines (B), to test for effects of copper exposure (copper level) and source of copper (source) late in larval development. Significant effects (p< 0.05) are highlighted in bold.