The Island of the Colorblind

On Guam, John continued, warming to his theme, the most common form of toxic seafood illness was ciguatera poisoning – ’It’s so common here, we just call it fish poisoning.’ Ciguatoxin is a powerful neurotoxin produced by a tiny organism, a dinoflagellate called Gambierdiscus toxicus, which lives among the algae that grow in channels on the coral reefs. Herbivorous fish feed on the algae, and carnivorous fish in turn feed on them, so the toxin accumulates in large, predatory fish like snapper, grouper, surgeonfish, and jack (all of which I saw on the menu). The ciguatoxin causes no illness in fish – they seem to thrive on it – but it is very dangerous to mammals, and to man. John is something of an expert on this. ‘I first saw it when I was working in the Marshall Islands twenty years ago – a fourteen-year-old boy, who became totally paralyzed, with respiratory paralysis as well, after eating a grouper. I saw hundreds of cases in those days. There were fifty-five different species of fish we found which could carry the ciguatoxin. There is no way a fisherman can tell whether a particular fish is toxic, and no way of preparing or cooking it that will deactivate the toxin.

‘At one point,’ he added, ‘people wondered if the lytico might be caused by some similar kind of fish poisoning – but we’ve never found any evidence of this.’

Thinking of the delectable sushi I had looked forward to all day, I was conscious of a horripilation rippling up my spine. ‘I’ll have chicken teriyaki, maybe an avocado roll – no fish today,’ I said.

‘A wise choice, Oliver,’ said John. ‘I’ll have the same.’

We had just started eating when the lights went out. A groan – ’Not again!’ – went around the restaurant, and the waiters quickly produced candles, which they lit. ‘They seem very well prepared for power outages,’ I said.

‘Sure,’ said John, ‘we have them all the time, Oliver. They’re caused by the snakes.’

‘What?’ I said. Did I mishear? Was he mad? I was startled, and for an instant wondered if he had somehow eaten some poison fish after all, and was beginning to hallucinate.

‘Sounds odd, doesn’t it? We have millions of these brown, tree-climbing snakes everywhere – the whole island is overrun by them. They climb the telephone poles, get into the substations, through the ducts, into the transformers, and then, pfft! We have another outage. The blackouts can happen two or three times a day, and so everyone is prepared for them – we call them snakeouts. Of course, the actual times are quite unpredictable.

‘How have you been sleeping?’ he added, inconsequentially.

‘Rather well,’ I said. ‘Better than usual. At home, I tend to be woken by the birds at dawn.’

‘And here?’ John prompted.

‘Well, now you mention it, I haven’t heard any birds at dawn. Or any other time, It’s strange; I hadn’t realized it until you asked.’

‘There is no birdsong on Guam – the island is silent,’ John said. ‘We used to have many birds, but all of them are gone – there is not a single one left. All of them have been eaten by the tree-climbing snakes.’ John had a prankish sense of humor, and I was not quite sure whether to believe this story. But when I got back to my hotel that evening, and pulled out my trusty Micronesia Handbook, I found confirmation of all that he had said. The tree-climbing snake had made its way to Guam in the hold of a navy ship toward the end of the Second World War and, finding little competition among the native fauna, had rapidly multiplied. The snakes were nocturnal, I read, and could reach six feet in length, ‘but are no danger to adults as their fangs are far back in their jaws.’ They did, however, feed on all manner of small mammals, birds, and eggs; it was this which had led to the extinction of all the birds on Guam, including a number of species unique to the island. The remaining Guam fruit bats are now in danger of vanishing. The electrical outages, I read, cost millions of dollars in damages each year.[66]

The next morning I had arranged to spend some time hunting for ferns in the Guamanian jungle. I had heard of Lynn Raulerson, a botanist, from my friends at the American Fern Society in New York. She and another colleague, Agnes Rine-hart, both work at the herbarium at the University of Guam and had published, among other things, a delightful book on Ferns and Orchids of the Mariana Islands (its frontispiece, a representation of the life cycle of a fern, was drawn by Alma). I met Lynn at the university, and we set off for the jungle, accompanied by one of her students, Alex, who was equipped with a machete. Alex remarked on the denseness of the forest in places. ‘You can still get completely lost, even with a good sense of direction,’ he said. ‘You go five yards in, and it’s so thick, you’re already dislocated.’