Figure 2. Dose-response relationship between intracoelomic (IC) injection doses of domoic acid (DA) and the percentage of zebrafish affected (n = 4 at each dose) for chronically exposed (red line) and control (green line) zebrafish.

Circular and/or spiral-swimming behaviors were used to quantify excitotoxicity in fish. The 50% Effective Dose (ED₅₀) = the dose at which 50% of the fish tested were affected (µg DA/g). The dose-response experiment was carried out at 20 weeks of exposure (one week after the last injection).