As dedicated sushi lovers know, eat

As dedicated sushi lovers know, eating fugu (puffer fish) is like playing chicken with death. Certain parts of the fish contain a nerve toxin, and unless the raw fish is prepared by someone who knows what he is doing (fugu chefs in Japan are licensed by the government), a delicate meal of fugu might be a diner's last.

The poison, tetrodotoxin, is produced by a bacterium in the fish. It has been isolated from other sea creatures as well, including squid, but even though it is a powerful poison, it leaves puffer fish and its other hosts alone.

Now, however, a marine organism has been found to have been affected by the poison. Scientists from the United States and the Caribbean island of Curacao, studying a mass die-off of sea urchins off Curacao in January 1997, found that the dead urchins, which had progressively lost their characteristic spines, contained a tetrodotoxin-producing bacterium that is closely related to the one found in puffer fish.

The study, reported in Nature, has implications for the ecology of coral reefs (because urchins feed on the algae around them, helping to maintain an ecological balance), and for public health. Urchin roe is eaten by some people. If a person ate roe from an urchin that was dying from a tetrodotoxin outbreak, the results could be the same as eating bad fugu.