Densities of purple urchins (A) before and (B) after the mass mortality event, by latitude.

<p>Bars depict standard deviation across sampled quadrats. Data are from the 11 sites surveyed between September and December 2011 (sites 1–4, 6, 10, 14, 16, 18, 23, 24). The shaded area denotes the impacted region, in which we found zero individuals at all sites surveyed after the event (n = 5).