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Distinguishing between pathogenic and poisoning mass mortality events of wildlife species is important for their health management. In marine ecosystems, the clinical signs of some poisons can present similarly to parasitic infections. In particular, saxitoxins (STX) include more than 30 derivatives that result in Paralytic Shellfish Poisoning (PSP) in animals and humans. PSP is a clinical syndrome characterized by inhibiting the entry of Na+ ions into cells via sodium channels (Llewellyn 2006). Affected organisms present severe clinical signs including muscular paralysis, pronounced dyspnea and a choking sensation, which if not promptly treated, can result in death due to respiratory paralysis (Hallegraeff 1993; Hallegraeff et al. 2003). PSP has been identified as the most toxic and dangerous syndrome along the Pacific coast (Sierra-Beltrán et al. 1998), with two dinoflagellate species, Gymnodinium catenatum and Pyrodinium bahamense, being principal species producing saxitotoxin associated with these PSP events (Cusick and Sayler 2013; Ochoa et al. 1997). These phenomena affect the entire trophic web, particularly primary consumers such as crustaceans, fish, jellyfish and salps that feed directly on plankton (Belgrano et al. 1999; Garate-Lizarraga et al. 2004; Sellner et al. 2003), however, organisms such as fish, marine mammals and sea turtles that feed on planktivorous species may also be affected (Garate-Lizarraga, Lopez-Cortes, et al. 2004; Sellner et al. 2003; Smayda 1997). However, few studies exist on the effects of harmful algal bloom (HAB) intoxication on these organisms, and for sea turtles, the majority of existing studies have …