The state of Florida is considering a ban on catching and eating pufferfish after five people have been poisoned this year.
The Southern puffer, Sphoeroides nephelus, a brackish and marine species which reaches around 30cm/12", used to be safe to eat providing it was correctly prepared. However, the puffers in the Indian River Lagoon appear to have unusually high levels of tetrodotoxin in their flesh, which makes the whole of their bodies dangerous to eat.
The neurotoxin tetrodotoxin (see molecular model) is considered to be around one level of magnitude more lethal than the venom of a Black widow spider.
The toxin itself may not be produced by the puffer fish themselves. Similar molecules are used by Blue-ringed octopus to kill prey, and have been isolated in crabs, algae and bacteria.
Experts believe that the presence of a toxin in algae with the lagoon is elevating tetrodotoxin levels in the puffers making them potentially deadly to eat.