Figure 2.

Upstream movement of pre-spawn female (a) and male (b) sea lamprey. Squares, trials where 3kPZS was administered to the stream (dashed regression line, females R²=0.59, males R²=0.38); upward triangles, trials where 50% methanol (control) was administered to the stream (solid regression line, females R²=0.68, males R²=0.57); and filled circles, trials where larval extract was administered to the stream (dotted-dashed regression line, females R²=0.10, males R²=0.85). q₁–q₃=the lower, median and upper quartiles of temperatures. See Results and table 2, for statistical comparisons at each quartile of temperature.