Ciguatera, food poisoning caused

The nature of poisons in sharks is a complex one. Vitamin A may be a causative factor in some shark species. The liver of sharks contains waxes, diacyl glyceryl ether, and hydrocarbons of which squalene and pristane are the most predominant (11). Sakurai and Masukara (82) and Kaneda,et al (83) demonstrated that squalene and wax can cause seborrhea and lethalities in rats. These studies suggest that the shark livers are not suitable for food. There is also clinical evidence that the ingestion of livers from tropical shark species may produce a ciguatera-like syndrome. 

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