Kagoshima University Research Center for the Pacific Islands Occasional Papers No.39, 83-86, 2003
Section 2, Report 9. The Progress Report of the 2000 and 2001 Survey of the Research Project“Social Homeostasis of Small Islands in an Island-zone”

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CIGUATERA FISH POISONING IN ULITHI ATOLL, YAP STATE,MICRONESIA
NORO Tadahide1), Gregory Naoki NISHIHARA1) , TERADA Ryuta2) , andAndrew YOROPIY3)

Abstract
Ciguatera toxification of herbivorous marine fish has been known in Fassarai Is. and Falalop Is.,
Ulithi Atoll in Micronesia since the 1950s. From the coral reef of these islands, the brown alga
Turbinaria conoides was collected and an epiphitic dinoflagellate Gambierdiscus toxicus, that is
known to synthesize ciguatera toxin, was identified on the surface of algal thalli in Oct. 2001. Someoutbreaks of fish poisoning occurred every year in the atoll, however no victims were reported during
the last few years. Recent victims took a fresh extract of Messerschmidia argentea called Lipii inUlithi Atoll. This leaf-extract is believed to have the highest curative qualities in all cases of ciguatera
poisoning in the atoll.
Keywords: ciguatera, fish poisoning, Ulithi, Turbinaria, Gambierdiscuss, Messerschmidia

Introduction
Ciguatera is a type of fish poisoning known in tropical South Pacific regions such as French
Polynesia, Papua New Guinea, Fiji, Micronesia and Palau (Y ASUMOTO et al. 1977; INOUE 1987,1992; I NOUE et al. 1985, 1995, 1996). This toxification paralyzed foudroyantly and caused fever
and diarrhea in those who ate herviborous coastal marine fish such as Plectropomus leopardus(Fig. 1) or Variola louti (Serranidae). The mortality rate was sometimes rather high, especiallyfor children and older people.

Fig. 1. Plectropomus leopardus (Serranidae) or lap- lap, poisonous fish in Ulithi Atoll, Yap, Micronesia

1)

Education and Research Center on Marine Resources and Environment, Faculty of Fisheries, Kagoshima
University. Kagoshima 890-0056, Japan.
2)
Faculty of Fisheries, Kagoshima University. Kagoshima 890-0065, Japan.
3)
Asor ls., Yap, 96943 Micronesia.

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NORO Tadahide, Gregory Naoki NISHIHARA, TERADA Ryuta and Andrew YOROPIY

The cause of the ciguatera was revealed to be a neurotoxin synthesized by the epiphiticdinoflagellate Gambierdiscus toxicus Adachi et Fukuyo, which attaches to the surface of brown
and red algae in coral reefs and were accumulated by algae-eating fish (ADACHI and FUKUYO
1979; YASUMOTO et al. 1977a, b).
During the Ulithi Research Expedition conducted by Kagoshima University ResearchCenter for the Pacific Islands in 2001, the authors had an opportunity to study the current stateof Ciguatera poisoning in Ulithi Atoll of Yap state, Federated States of Micronesia.

Materials and Methods
Benthic macro algae were collected along the coasts of Mogmog Is., Asor Is., Falalop Is.
and Fassarai Is. of Ulithi Atoll, Yap, Micronesia, from 19 to 27 October 2001 as shown in
TERADA et al shown in these occasional papers. Among these algal specimens, the brown alga
genus Turbinaria which is thought to be the host seaweed of the epiphytic Gambierdiscus
toxicus was examined by microscope on the research vessel MV Keiten-maru.

Results and Discussion
Fish poisoning in Ulithi Atoll.
Reliable statistical data about fish poisoning was not available at the dispensary of the islands. According to the islanders, at least one or two people suffered from fish poisoning after
eating a marine fish called lap-lap (Fig. 2), possibly Plectropomus leopardus or Variola louti(Serranidae). While detailed information on the survival rate of the patients was obscure, thenumber of deaths may be small in the atoll. Most of the poisonous fish, lap-lap, was caught near
Falalop Is. and Fassarai Is. of Ulithi Atoll. The people recognized that ciguatera fish poisoning
was prominent after the 1950s but there were no records of poisoning occurring before that period.

Fig. 2. Distribution of poisonous fish, lap- lap, in Ulithi Atoll. Ciguatera poisoning of lap- lap was restrictedin the coral area near Falalop Is. and Fassarai Is. Toxic dinoflagellates, Gambierdiscus toxicus wasfound on the thalli of the brown alga Turbinaria conoides in the south of Fassarai Is.

CIGUATERA FISH POISONING IN ULITHI ATOLL, YAP STATE, MICRONESIA

85

Cause of Fish poisoning in Ulithi Atoll.
On all of the islands, where algal flora was studied in our field trip, Turbinaria conoides
was often seen cast up on shore (Fig. 3–4). While this brown alga may be distributed on the reefedge of the atoll, the authors could not collect live specimens by snorkeling. The outer edge ofthe atoll was washed by strong waves caused by a typhoon during the field trip. The
dinoflagellate Gambierdiscus toxicus that is known as the cause of ciguatera fish poisoning, wasdetected on the thalli of these semi-dried Turbinaria on the beach (Fig. 4). Fortunately theauthors had an opportunity to collect Turbinaria on the southern beaches of Fassarai Is. andseveral cells of Gambierdiscus toxicus were identified attached to the surface of the algae. Eastof Ulithi Atoll, near the fishing grounds of Falalop Is. and Fassarai Is., the possibility ofGambierdiscus toxicus attached to benthic brown alga may have contributed to the poisoning ofciguatera associated fish.

Fig. 3. Brown alga Turbinaria conoides cast up on shore ofMogmog Is., Ulithi Atoll

Fig. 4. Turbinaria conoides on a coral beach of Mogmog Is.
Fig. 5. Messerschmidia argentea collectedfrom Asor Is., Ulithi Atoll. Local namecalled lippi.

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NORO Tadahide, Gregory Naoki NISHIHARA, TERADA Ryuta and Andrew YOROPIYAntidote locally used for fish poisoning.
In Ulithi Atoll, extract from a tree was used as an antitoxin for ciguatera fish poisoning. Theplant was called lippi in the islands and velvet-like young leaves were homogenized in a stone
mill. The extracted fresh juice was given to the victims of fish poisoning. According to the local
doctor at the dispensary, the effect of the herb was quite conspicuous and the patients recovered
in several hours after they took the extract. A specimen was collected at a beach of Asor Is.
shown in Fig. 5 and classified as Messerschmidia argentea Lippi is a common tree in Yap State,but only the islanders of Ulithi Atoll use it as an antidote for the fish poisoning.
In the halophilic habitat of lippi, this tree may have a mechanism to exude absorbed salt externally. The expected sodium pump of the cell or metabolism of the cell may have a possibilityof reducing ciguatera toxicity to the human neural system. More physiological and biochemical
studies may be required.

References
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