Outbreak of fish poisoning in Aitutaki

Here is some information about my research on ciguatera fish poisoning in the southern Cooks with particular reference to Aitutaki who are currently experiencing an outbreak. The Aitutaki outbreak is caused by cyclone Pat that devastated the island earlier this year. In support, my research has shown that ciguatera in the southern Cooks is closely linked to reef disturbances, particularly those caused by cyclones, taramea infestation, and to a lesser extent coral bleaching. The result of these disturbance events create space on reefs for opportunistic species of microscopic algae that causes fish poisoning to establish. Subsequently, they enters the food web through grazing by herbivorous fishes (e.g., maito) or detritus feeders (e.g., koma and kanea), which are in turn eaten by carnivorous fishes (e.g., titiara) as the toxin move to higher trophic groups. This movement of toxin up the food wed, not only result in the accumulation in large carnivorous fishes, but they also become more potent and dangerous for human consumption.
The situation in Aitutaki was also experienced in Rarotonga during the passing of 5 cyclones in 2004/2005 when poisoning cases during this period increased abruptly. However, after two years (noted in 2007 to present), the incidence of fish poisoning in Rarotonga declined (data provided by Cook Islands Ministry of Health). Provided that Aitutaki do not encounter another cyclone in the upcoming cyclone season, fish poisoning in two years should also decline to levels prior to the cyclone. However for the time being, be extra cautious when considering eating reef fish from Aitutaki, particularly from known toxic species such as titiara, aa pata, iroa, tangau, kiriva, large patuki, mu, maito, pakati, and kanae. People in Aitutaki should know from past experience what these toxic reef fishes are. To be safe, limit yourselves to ocean species (e.g., aai, para, maimai, maroro) or in the case of reef fishes, stick to what has been considered safe in the past (e.g., pipi, mapoto, ku pa). However, be very careful with the ku tara or ku ta family, these have been implicated in many poisonings in the past and people have a tendency to group them with the safe ku just because they are in the same family.

Teina Rongo
Marine Biologist USA

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