SPC ACTIVITIES

REEF FISHERIES OBSERVATORY Ciguatera-like fish poisoning from giant clams on Emao Island, Vanuatu Ciguatera — a particular type of marine fish poisoning — is Hawaii Torres Islands caused by eating tropical coral reef fish that have accumu- 0° lated ciguatoxins through the Banks Islands 14°S – marine food chain. The social Vanuatu and economic impacts of such Australia Espiritu Maewo intoxications are highly signifi- Santo Ambae cant in the Pacific, where fish is Luganville New Zealand Malo Pentecost an important part of people’s 16°S – Ambrym daily food and is one of the Malakula few sources of cash income for Epi coastal communities. Shepherd Group Emao Island In October 2008, during a cigua- EfEfateat tera and marine biotoxins con- Port ViVilala 18°S – ference organised by SPC, the Institute of Research for Devel- Erromango opment (IRD), the Pasteur In- Efate Tanna stitute, and the Papeete-based Port Vila

Louis Malarde Institute (ILM), 20°S – a representative from Van- Aneityum uatu’s Fisheries Department 166°E168°E 170°E highlighted a severe outbreak Figure 1. Vanuatu, Efate and Emao Island of fish poisoning on Emao Is- (Picture source: Millennium Coral Reefs Landsat Archive). land near Efate (see Fig. 1). Al- though there are six villages on and which are associ- Emao, only Lausake village (lo- ated with water-sol- cated on the southeastern side, uble paralysing tox- see Fig. 2) was being affected ins such as paralytic by fish poisonings. People were shellfish toxins and/ Mangarongo becoming seriously ill from eat- or anatoxin-a, and Mapua ing fish as well as giant clams. homoanatoxin-a. EMAO Marow CIGUATERA-LIKE POISONING Another case of poi- FROM NEW CALEDONIA AND soning from giant Ngurua RENCH OLYNESIA clams was reported F P Lausake from Raivavae in Wiana Poisoning caused by eating French Polynesia. This giant clams was recently stud- poisoning formed the ied on Lifou in New Caledonia’s focus of another simi- Loyalty Islands. The study lar toxicological study. found that within an area The study revealed a claimed to be the source of cigua- strong relationship be- Figure 2. Emao Island toxic fish and molluscs, there tween anthropogenic and Lausake village. was an absence of Gambierdiscus impacts, the develop- sp., the dinoflagellate usually ment of Oscillatoriales (cyano- temperature reversal. Therefore, associated with ciguatera out- bacteria) blooms, and the result- the term “ciguatera” is still used breaks. Present, however, were ing outbreak of ciguatera fish for this new intoxication. large populations of filamen- poisonings caused by eating tous cyanobacteria identified as giant clams in affected areas, all The case on Emao Island in Hydrocoleum. Further in vivo and of which suggest a new trophic Vanuatu provides a suspiciously in vitro toxicological studies on pathway of human poison- curious and interesting case that samples of these cyanobacte- ing via molluscs such as giant could provide another possi- ria and giant clams showed the clams. Indeed, the symptoms ble example of cyanobacteria- presence of lipid-soluble com- experienced by patients includ- related fish poisoning. The pounds that are ciguatoxin-like, ed the characteristic sensation of sampling and chemical analy-

SPC Fisheries Newsletter #129 – May/August 2009 13 SPC ACTIVITIES

ses required for a proper FIELD METHODS Collecting samples toxicological study will require a good experimental design Informal interviews Samples of cyanobacteria were and extensive field efforts. This collected by hand from various first preliminary investigation During the visit, information on locations and different biotopes. serves as a preparatory first the number of ciguatera cases The samples were preserved step toward this larger study. admitted was collected from in sealed containers for later the Public Hospital in Port Vila analysis. Macroalgal samples EMAO ISLAND STUDY through an interview with the were also collected and tested Director of Public Health, Dr for Gambierdiscus sp. Some reef In response to a request from Griffith Harrison. fish species and clam specimens Vanuatu’s Fisheries Depart- were also collected to analyse ment, a joint SPC, IRD and ILM Historical and epidemiologi- their toxicity. mission to visit Emao Island cal information was collected was organised in order to: through consultations and in- The samples were taken to New formal interviews with the com- • Caledonia for analysis at IRD’s Contact communities af- munity of Lausake village. Only laboratory. A permit to take fected by the fish poisoning a few people of the interviewees the samples out of Vanuatu epidemic, and collect histori- could fully understand English, was provided by the Vanuatu’s cal information on when the and so it was important to have Fisheries Department. A CITES fish poisoning began, who the fisheries officers assist in permit for export had to be ob- was infected, which fish were translating questions from Eng- tained for giant clams, a CITES- implicated, and the types and lish to Bislama to the local peo- listed species. duration of symptoms; ple, and to translate responses • Present the current knowl- from Bislama to English for us, SOME RESULTS AND edge and improve the com- the research team. The ques- OBSERVATIONS munity’s understanding of tions asked were generally ad- ciguatera and marine-related dressed to the entire commu- Informal interviews illnesses related to eating fish nity, with more detailed ques- and shellfish; tions targeted at individuals An interview with the Direc- tor of Public Health at Port Vila • Gain an idea of the extent of who were willing to share their experiences of their poisoning. Public Hospital revealed that the infected reef area through the actual number of ciguatera field inspection, and evaluate During consultations, the team took the opportunity to give a cases has been increasing in re- the quality of the reef by tak- cent years; and since October ing pictures and conducting poster presentation, explaining the ciguatera problem and the 2008, the hospital has recorded some preliminary investiga- eight cases. Two cases involved tive sampling; ongoing research and investiga- tions that are being carried out whole families although the • Conduct a chemical analysis to try and better understand the other family members were not of collected samples in order problem. A copy of the poster admitted into hospital. A very to identify the presence of used in Bislama was given to serious case from Emao resulted ciguatera- and cyanobacteria- the Vanuatu Fisheries Depart- in the patient being evacuated related toxins; and ment for use at other ciguatera to New Zealand for treatment. • Use preliminary results and public awareness meetings. Information obtained from pa- observations to design a more tients indicated that the source detailed research project to Site observations of the ciguatoxic fish was the lo- investigate and understand cal fish market, where fish from the problem. A site visit was made to evalu- Emao are sold. As a result, peo- ate reef conditions, water qual- ple in Port Vila are now avoid- In May 2009, SPC’s Senior Fish- ity, and the size of the infected ing fish from the market unless eries Scientist, Being Yeeting, area based on information col- they are certain that the fish do and a doctoratal student work- lected from fishers. Underwater not from Emao. ing on marine biotoxins, Anne- observations were made using Sophie Kebrat from IRD visited mask and snorkel, swimming Also recently, there was a case Emao Island. Being and Anne- in a square from the beach out of a boy who became ill and Sophie worked with two local to the outer reef, across the area died from eating some kind of counterparts from Vanuatu’s close to the outer reef, from the shellfish collected at the wharf Fisheries Department, Sompert outer reef to the beach and along in town. Yet another recent in- Gereva, Senior Fisheries Biolo- the beach side. Photographs of cident involved two deaths gist and Jeremy Kaltavara, Fish- corals and substrate observed from eating mud crabs. Santo eries Research Assistant. were taken. is another area with significant

14 SPC Fisheries Newsletter #129 – May/August 2009 SPC ACTIVITIES numbers of ciguatera fish poi- One recent case was hospital- bid, especially 50 m out from soning cases. ised, but thus far, no fatalities the beach. have been recorded. To test for Samples collected Lausake villagers were very in- toxic fish, villagers commonly terested in the study and were use cats and dogs and, interest- Batches of cyanobacteria — col- very cooperative during inter- ingly enough, there were hard- lected from different biotypes views, an indication of their ly any cats or dogs in Lausake — will be properly identified in desire for help in solving their compared with Marow village. the laboratory. Several visually fish-poisoning problem and different coloured specimens to regain the seafood sources Villagers noted differences in were seen in the infected reef they have lost from their reefs. symptoms from eating toxic fish area (Fig. 5). About 40 people were inter- and toxic shellfish. The symp- viewed. Fish, shellfish or both toms associated with eating had poisoned each of these peo- toxic fish are typical of ciguat- ple at least once. Because of the era: fatigue, nausea, diarrhoea, fish poisoning, villagers have joint pain, and hot-cold sen- stopped eating seafood from sory reversals. With shellfish, their reefs and have turned to symptoms are quick to appear: root crops instead for food. The tingling lips and burning sen- only fish they are comfortable sations in the mouth, followed eating now are tuna (which are by gastrointestinal problems never ciguatoxic), although (diarrhoea and vomiting) that catching tuna requires a boat occur within the first hour, and and engine, which most villag- neurological symptoms that last ers do not have. for several weeks (whereas with ciguatera, these tend to last for The infected area seems to be several months). localised to the reef adjacent to Field observations Lausake village, from the beach outwards to the barrier reef. The The infected reef area from the reef fish started becoming toxic beach to the barrier reef cov- 10 years ago, but giant clams, ered a distance of about 1,000 m. trochus, gastropods (e.g. Nerita The reef area consisted mostly polita), crabs and other shellfish of Acropora spp., most of which (e.g. Atactodea striata) (Fig. 3) be- were dead and covered with car- came toxic about three to four pets of filamentous cyanobacteria years ago. (Fig. 4). The Oscillatoriales (cy- anobacteria), mainly Hydrocoleum and Phormidium were seen in large and small diversified mats. At a distance of 10–20 m from the beach and along the beach over a stretch of about 100 m, gardens Figure 5. Cyanobacteria visible of Sinularia-like soft corals were on different biotypes. found. The coast was very tur- Three reef fish species — the parrotfish, Hipposcarus longiceps, the emperorfish, Lethrinus harak, and the surgeonfish, Ctenochaetus striatus (Fig. 6) — and one clam specimen, Hippopus hippopus (Fig. 7), were collected. Chemical analyses of these samples are being conducted at the IRD laboratory in Noumea.

Figure 3. Nerita polita and The results should be available Figure 4. Atactodea striata, two invertebrate Dead coral covered soon, and will hopefully provide with carpets of fi lamentous species found to be toxic off some insights to the cause of the Lausake village. cyanobacteria. fish poisoning and whether the

SPC Fisheries Newsletter #129 – May/August 2009 15 SPC ACTIVITIES

Lethrinus harak Ctenochaetus striatus

Figure 6. Two of the three species of reef fi sh collected for ciguatoxin testing.

like toxins seem to be present Raivavae, French Polynesia and in the giant clams collected. Lifou, New Caledonia. These Theses results, however, need symptoms are very similar to to be further confirmed. The ciguatera-based fish poisoning lipid-soluble extract from cy- symptoms, but seem to occur anobacteria and the fish are cur- more rapidly and last only a few rently being analysed for their weeks, whereas ciguatera-based ciguatoxic potential. The results fish poisoning symptoms can of these further analyses were last for several months. not ready when this article was written, but will be described in It should be noted that such Hippopus hippopus a more detailed technical report. cases of seafood poisoning could be more common than currently Figure 7. A giant clam sample CONCLUDING REMARKS known and are often regarded as collected for analysis. ciguatera-related fish poisoning. Recently, cyanobacteria have People who experience peculiar been found to play an important toxins are ciguatera-based or cy- symptoms of fish poisoning af- role in seafood poisoning, espe- anobacteria-related. The results ter eating molluscs or grazing cially in relation to giant clam will also be sent to Vanuatu’s fish (e.g. parrotfish) and mollus- poisoning. Studies in Raivavae, Fisheries Department and the civorous fish (e.g. emperorfish) French Polynesia and Lifou, Lausake village community should contact their medical New Caledonia have shown when they are available, and doctor or nurse, or the Fisheries that it is possible for cyanobac- will be used to develop a larger Department. Such information terial toxins to enter the food research project to examine the could improve the understand- chain directly through grazing problem in greater detail. ing of seafood poisoning from fish (e.g. parrotfish) or via mol- different marine biotoxins. Preliminary results from luscs through molluscivorous analyses fish (e.g. emperorfish). ACKNOWLEDGEMENTS

The samples collected revealed Although the results of the SPC, IRD and ILM thank the the absence of Gambierdiscus chemical analyses of the Emao community of Lausake village dinoflagellates, which are known samples are not yet known, for their hospitality and co- to produce ciguatoxins. the presence of mats of cyano- operation during the visit, and bacteria in the area of Lausake the Vanuatu Fisheries Depart- Chemical analyses of samples village certainly provides a ment for its support. Funds taken from i) a mat of cyanobac- strong possibility that cyano- for this study were provided teria, ii) fish, and iii) giant clams bacteria is the cause of the food by the Pacific French Fund were also conducted. The water- poisoning currently occurring through ILM; French Poly- soluble and lipid-soluble com- on Emao Island. nesia, covered airfares and pounds obtained were screened some fieldtrip expenses. for their toxicity with mouse It was also interesting to note that the symptoms reported bioassay and cytotoxicity test Fore more infomation, please by Lausake villagers who be- respectively. contact: came sick from consuming These tests revealed a strong giant clams, seemed to corre- Being Yeeting, Senior Fisheries paralytic toxicity for both the spond with those of the cyano- Scientist (Live Reef Fish), SPC cyanobacteria and giant clam bacterial-associated giant clam Email: [email protected] samples. In addition, ciguatoxic- poisoning cases reported in

16 SPC Fisheries Newsletter #129 – May/August 2009