Fig. 5. Effect of goitrogen treatment on pupfish morphology. Relative (A) head size (P=0.0053), (B) eye size (P=0.0013) and (C) body depth (P=0.0049) of pupfish varied significantly among the methimazole, KClO₄, and control treatments. Relative head size, eye size, and body depth are presented as percent of standard length (SL). Values are means ± s.e.m. (N=7-8). Letters indicate pairwise comparisons among groups (Tukey HSD test).