Cyanobacteria have also been shown to be capable of producing saxitoxins, common shellfish poisoning toxins associated with marine dinoflagellate blooms and contaminated shellfish (Llewellyn, 2009). Saxitoxins are extremely potent natural products, with their major mode of action acting through the inhibition of sodium channels. In high enough doses, death can occur in minutes due to paralysis and respiratory arrest (Metcalf and Codd,2012).