Fig. 4.

Projected dose curves (μg kg⁻¹) for saxitoxin (STX) exposure in Arctic Terns (Sterna paradisaea) given a range of ecologically relevant mean concentrations in forage fish (3, 30, and 300 μg 100g⁻¹ STX) consumed over a 24 h period. Daily fish requirements (black vertical line) estimated from previous reports of field metabolic rates in adult (Uttley et al., 1994) and nestling (Klaassen et al., 1989) Arctic Terns, assuming a standard energetic value of 5 kJ g⁻¹ wet weight for Pacific Sand Lance (Ammodytes hexapterus) and Pacific Herring (Clupea pallasii; Piatt et al., 2020; Van Pelt et al., 1997). Dashed red line shows LD₅₀ (lethal dose in 50% of individuals) for Mallards (Anas platyrhynchos; Dusek et al., 2021). Note that estimated STX dose curves are displayed on a logarithmic scale. *Mean adult mass of 102 g taken from Uttley et al. (1994).