SPC/ 19/WP.22 3 July 1987 ORIGINAL : ENGLISH

SOUTH PACIFIC COMMISSION NINETEENTH REGIONAL TECHNICAL MEETING ON FISHERIES (Noumea, New Caledonia, August 1987)

SUMMARY NOTES ON POISONING INVESTIGATIONS IN THE SOUTH PACIFIC

by Mike Gawel Administrator of Marine Resources Department of Resources and Development Federated States of Micronesia SPC/Fisheries 19/WP.22 Page 1

1• Poisoning from Consumption Q± Tropical .

Historically, persons throughout the Tropical Pacific and have suffered poisoning at various times and places from consumption of of reef fishes which are normally safely edible. Those fishes which are intrinsically poisonous, such as puffer fish of the family Tetraodontidae, are excluded from this discussion, as are shell fishes and fishes which have become toxic due to contamination during handling, or spoilage. (This often leads to histamine poisoning in Micronesia). Ciguatera is the term used for the locally occuring food chain related poisoning in unspoiled reef fishes. No technique is known to remove or detoxify the poison in ciguateric fish. Deaths are attributed to ciguatera and persons become more sensitive to it with each exposure.

Reef fishes of practically all species sampled at hot spots of ciguatera occurrance have been recorded as being toxic. Tests of specimens from the south eastern reef of Pingelap Atoll, Micronesia, showed that representatives of the families Acanthuridae, , Lutjanidae, Scaridae and Serranidae were all poisonous, while only squirrel fishes of the family Holocentridae appeared to be safe to consume from the toxic reef area (Raj and Haq 1984). The same species from nearby or adjacent reefs, however, can be perfectly safe to eat.

After many years of research by numerous scientists and institutions, Japanese scientists discovered a microscopic single celled organism, living on the surface of different species of coral reef seaweeds, which produces an extremely powerful toxin (Yasumoto et al 1977). This epiphitic dinoflagellate on benthic macroalgae is named Gambierdiscus toxicus. Fish feeding on materials on the surface of seaweeds (such as the comb-toothed surgeonfishes of the Ctenochaetus) or consuming the whole seaweed, ingest Gambierdiscus and its toxin. If the poison occurs in sufficient quantities, it not only makes these herbivores poisonous to man, but also makes the carnivorous fishes which eat them, likewise, poisonous. In fact, the toxin appears to accumulate through the reef food chain, leading to the largest carnivores often being the most toxic of ciguatoxic fishes. Typically, large red snappers (LutJanus bohar) moray eels (Gvmnothorax SPP.) and groupers (Epinephelus and Plectropomus) are found to be most ciguatoxic in Micronesia.

Ciguatera has appeared in new areas where it had been unknown previously (Gawel,1984) and may be decreasing in areas where it has been a problem. Very little is known about the causes of increases in ciguatera. The ecology of Gambierdiscus no doubt plays a critical role, but the habits of fishermen and fish consumers do also. It is believed by many that disturbances to coral reef ecology may trigger outbreaks of ciguatera. This author and University of Guam Marine Laboratory scientists have attempted to monitor possible rise of ciguatera following reef blasting in Tarawa and construction of airports on reefs in Kosrae and Truk, but these observations have been incomplete. SPC/Fisheries 19/WP.22 Page 2

2. impact on Fisheries la lh£ 2E£ Region- 2.1. The actual poisoning and the fear of possibly being poisoned by ciguatoxic fish has always led to those inhabitants of areas closest to ciguatera sources to avoid eating at least large predators and in some cases other fishes or even all fishes from sites where poisonous fishes have been found. With increasing population in most South Pacific Islands, more pressure is occurring for individuals to take risks and try to consume fishes of questionable toxicity.

2.2. Common government goals of expanding fisheries for commercial supply to local and export markets and for subsistence consumption to replace imported foods have resulted in improved technical capabilities of harvesting remote and non-traditional fishing areas. Newly developed or potential fishing areas would have fishes whose possible toxicity is unknown.

2.3. Based upon previous poisoning experiences, products of certain reefs are avoided by subsistence and commercial fishermen. Whether or not all reportedly toxic areas remain so, or have recovered and can safely be exploited, is unknown.

2.4. Immediate economic and social pressures may force fishermen to take a risk in commercially selling fish that they suspect could be poisonous.

2.5. Entrance of any poisonous fish into the market can seriously damage or destroy attempts at fisheries development and can even force significant numbers of fishermen out of jobs. So little is known about ciguatera and its possible occurrance, that fish brokers and buyers sometimes categorically may reject all fishes produced in even a large general area where an instance of poisoning has arisen. This has very serious implications for South Pacific nations or territories which plan to supply fish to export markets. For example, a rumor circulated in Honolulu in 1986 that a market there received ciguatoxic fish from the Island of Kosrae. This has been proven impossible because: A) no instances of ciguatoxic fish poisoning have ever occurred in Kosrae, where reef fish are an important part of Kosraeans' diets and B) Kosrae had not exported fish commercially to Honolulu and until late 1986 had never had practical transportation connections to allow shipping fishes to Honolulu. However, there probably remains some doubt in the Hawaiian buyers minds about accepting fishes from Kosrae. And if external buyers do receive a toxic fish from any South Pacific Island they are liable to either refuse similar fishes from other neighboring islands or lower their prices to island suppliers because of supposed risks. SPC/Fisheries 19/WP.22 Page 3

3. Research on the Ciguatera Problem.

3.1. Outside of our region various US universities and agencies support projects dealing with ciguatera in the Caribbean area. Within the South Pacific Region, in the recent past, the South Pacific Commission had supported activities dealing with the fisheries aspects of ciguatera, and had sponsored a handbook on ciguatera, two Expert Committee on Ciguatera Meetings in 1981 and 1983, and contributed to the investigations by Tohoku University and Louis Malarde Institute which led to discovery of the cause of ciguatera. The World Health Organization has sponsored meetings on marine fish poisoning and provides a toxic fish poster prepared by Professor Yasumoto of Tohoku University. For more than a decade, the University of Hawaii, Tohoku University in Japan, and the Louis Malarde Institute of Medical Research in Tahiti very actively have been investigating ciguatera and testing fishes for ciguatoxin.

Some centers of most recent ciguatera research related to South Pacific fisheries incude the following five, while probably others are active but unknown to the author at this time, who apologizes for such ommissions.

3.2. The Institute of Marine Resources of University of the South Pacific has established capability to dependably test fish samples with the mouse bioassay method and to identify and quantify Gamblerdiscus toxicus in the field.

3.3. The Louis Malarde Medical Research Institute has developed a unique mosquito bioassay test which is regularly applied to ciguatoxic specimens. Only 8 grams of fish sample are needed for this delicate test.

3.4. In Japan, the Faculty of Agriculture of Tohoku University continues excellent research on ciguatoxin and other marine toxins which occur in the South Pacific Islands, while the Research Center for the South Pacific of Kagoshima University carries out investigations on ecology of Gambierdiscus and related dinoflagellates found in Pacific coral reefs.

3.5. At the University of Hawaii Manoa Campus, the Department of Chemistry carries out research to define the molecular structure of ciguatoxin and related marine toxins from coral reef fishes, while the Pathology Department of the Medical School is perfecting a simplified "poke-stick" test for ciguatoxin which promises to be suitable for island fisheries offices and field conditions in the near future.

3.6. In Australia, the Queensland Department of Primary Industries, the Queensland Institute of Technology and the University of Queensland have ongoing projects to investigate factors influencing (L. toxicus growth and production of toxin, to isolate ciguatoxin and study its mode of action and develop antibodies for it and tests for it, and to determine ciguatera incidence in Queensland. SPC/Fisheries 19/WP.22 Page 4

4. Federate^ SUtes pi. Micronesia Work QR Fish Poisoning.

Although the Federated States of Micronesia lacks the expertise and capabilities for ciguatera research that are found at the above mentioned locations, the author is most familiar with fish poisoning investigations being pursued in that new nation and can report as follows.

4.1. Under the Trust Territory Of the Pacific Islands Administration, thousands of cases of fish poisoning in Micronesia were reported from 1973 to 1982 (SPC, 1983). The numbers caused by ciguatera are uncertain. More recently, deaths and serious poisonings have been attributed to consumption of reef fishes at Mokil and Pingelap Atolls in Micronesia. Concern over this problem led to an FSM sponsored investigation of fish poisoning at these atolls in 1984. Specimens were collected and tested at the USP Institute of Marine Resources with results as shown in Tables 1 and 2 (Raj and Haq, 1984a and Raj and Haq, 1984b).

4.2. In 1987, via support of the Pacific Fisheries Development Foundation and the FSM Government, additional investigations of fish poisoning in Micronesia are being undertaken. Samples of possibly toxic fishes have been collected from the FSM States of Kosrae, Pohnpei, Truk and Yap. These are being tested in Tahiti by the Louis Malarde Instite, in Fiji by the Institute of Marine Resources of USP, in Hawaii, by the University of Hawaii Medical School and in Japan by the Faculty of Agriculture of Tohoku University.

4.3. The validity of the University of Hawaii's "poke-stick" test and its applicability to use in the FSM is being investigated. This test presently requires supplies that are difficult to obtain and maintain (e.g. monoclonal antibody to ciguatoxin) and involves numerous tedious steps to be taken in a laboratory environment. However, it appears to work well, requiring only a small quantity of fish to be sampled. Even fish soup or fish products can be sampled with the poke-stick (a six- inch. specially-prepared bamboo food skewer). This test registers degrees of toxicity not only for ciguatoxin, but also related scaritoxin found in parrotfishes, maitotoxin of surgeonfish and palytoxin, which has been found in triggerfish in Micronesia. But the test is also sensitive to chemicals produced by other marine dinoflagellates which are not toxic to humans. Thus, it can produce false positive results in fish samples which may be safe to eat. It has not yet let toxic samples pass as being safe.

The five FSM Marine Resources Division Chiefs from the National Government and the four States tried carrying out this test simultaneously in 1986 and four of them were able to get good results (i.e. they carried out techniques properly) on their first trial, after only a few hours training. SPC/Fisheries 19/WP.22 Page 5/6

Presently, the FSM is participating in a world-wide examination of the poke-stick test to see whether it can obtain US Food and Drug Administration approval as a valid technology.

5. Conclusions

Whereas cheap, simple, reliable tests for ciguatera fish poisoning are not yet available anywhere in the world; satifactory treatment to combat symptoms of the poisoning is lacking and methods do not exist to detoxify fish or prevent occurrence of toxins in reef fishes; and whereas increased harvesting of even possibly toxic reef fishes is foreseen in the future of South Pacific Islands, because of population increases and desire for economic development; and increased human impacts on coral reefs may increase incidences of ciguatera; therefore, more fisheries officers must devote more attention to the research being undertaken on fish poisoning and must prepare to apply practical results of this research, when available. The booklet "Seafood Poisonings in Tropical Regions", edited by Yasumoto, Raj and Bagnis, provides a comprehensive, up-to-date and condensed account of this subject in format suitable for fisheries officers. It should be made available in quantity to SPC members. Also, it is desirable that a revised version of the SPC handbook on fish poisoning be provided soon.

REFERENCES CITED

1. Raj, U. and H. Haq. 1984a. Toxicity Tests for Ciguateric Fish from Pingelap, FSM. Institute of Marine Resources, University of the South Pacific, Suva, Fiji. 7pp.

2. Yasumoto, T., I. Nakajima, R. Bagnis, and R. Adachi. 1977. Finding of a Dinof1 age 1 late as a Likely Culprit of Ciguatera. Bull. Jpn. Soc. Sci. Fish. 43:1021.

3. Gawel, M.J. 1984. Fish Poisoning Related to Human Impacts on Coral Reefs in the Federated States of Micronesia. IN Proceedings, Man and the Biosphere/COMAR Regional Seminar, Tokyo, pp.43-46.

4. South Pacific Commission. 1983. Report of Meeting of Second Expert Committee on Ciguatera. Noumea.

5. Raj, U. and H. Haq. 1984b. An Assay for Ciguatoxin in Fish from Mokil Island, FSM. Institute of Marine Resources, University of the South Pacific, Suva, Fiji. 8pp.

6. Yasumoto, T., U. Raj, and R. Bagnis. 1984. Seafood Poisonings in Tropical Regions, Laboratory of Food Hygiene, Faculty of Agriculture, Tohoku University, Sendai, Japan.

6 SPC/Fisheries 19/Wp.22 Page 7/8

Table 1: TOXICITY SCORES OF FISH FROM PINGELAP, CAROLINE IS., TESTED FOR CIGUATERA

FISH SPECIES DATE AREA TISSUE TOXICITY CAUGHT CAUGHT SCORE MU/lOOg

FAMILY: ACANTHURIDAE

Acanchurus crioscegus 11.2.84 Pingelap flesh N.D, Caroline Is. viscera * Acanchurus glaucooareius 11.2.84 Caroline Is. flesh N.D viscera * Cccnochaetus striatus 11.2.84 Caroline Is. flesh 2.5 viscera * Zebrasoma sconas 11.2.84 Caroline Is. flesh 5.0 viscera *

•Pooled Viscera 10.0

Naso hexacanchus 11.2.84 Caroline Is. flesh N.D. viscera Naso licuracus 11.2.84 Caroline Is. flesh N.D. viscera

••Pooled viscera 7.5

FAMILY; CARANGIDAE Carangoides ferdau 11.2.84 Pingelap flesh 3.0 Caroline Is. tnelanroygus 11.2.84 Caroline Is. flesh N.D.

FAMILY; LUTJANIDAE Luc 1anus bohar 11.2.84 Pingelap flesh N.D. Caroline Is. viscera Luc 1anus fulvus 11.2.84 Caroline Is. flesh N.D. viscera Macolor nicer 11.2.84 Caroline Is. flesh N.D. viscera

•••Pooled viscera 10.0

FAMILY; SCARIDAE Scarus sordidus 11.2.84 Pingelap flesh 5.0 viscera 12.5

FAMILY: SERANIDAE cCeohalooholis argus 11.2.84 Pingelap flesh N.D Caroline Is. viscera cCracila albomarginaca 11.2.84 Caroline Is. flesh N.D viscera :£oinenneius faria 11.2.84 Caroline Is. flesh N.D viscera

cPooled viscera 12.5

FAMILY: HOLOCETTaiDAE

Sargoceneron ciere 10.2.34 Pingelap flesh N.D. Caroline Is SPC/Fisheries 19/WP.22 Page 9

TABLE ^. Toxicity Scores of fish from East Mokil Island, The Federated States of Micronesia.

FISH DATE TISSUE TOXICITY SPECIES CAUGHT TESTED SCORE MU/lOOg

ACANTHURIDAE Acanthurus achill es 6.8.84 Flesh N.D Acanthurus glaucopareius 6.8.84 Flesh N.D Acanthurus lineatus 6.8.84 Flesh N.D Viscera 5.0 Acanthurus guttatus 6.8.84 Flesh N.D Acanthurus nigroris ) 6.8.84 Acanthurus nigrofuscus; Flesh N.D. Acanthurus triostegus 6.8.84 Flesh N.D. Naso lituratus 6.8.84 Flesh N.D. Viscera Ctenochaetus striatus 6.8.84 Flesh 5.83 Viscera 8.32 CARANGIDAE Caranx melampygus 7.8.84 Flesh N.D.

HOLOCENTRIDAE Sargocentron (Adioryx) 7.8.84 FM A/. A violaceus Wsceti fJ.J), KYPHOSIDAE Kyphosus cinerasei^s) Flesh N.D. 7.8.84 Kyphosus Lembus 1 Viscera 2.5

LUTJANIDAE Lutjanus Culvus ] 7.8.84 4.16 Lutjanus monostigma' Flesh

SCARIDAE Scarus globiceps 7.8.84 Flesh N.D. Scarus tricolor 7.8.84 Flesh N.D. Scarus caudofasciatus 7.8.84 Flesh N.D. Viscera N.D. SPC/Fisheries 19/WP.22 Page 10 TABLE 2 (continued)

FISH DATE TISSUE TOXICITY SPECIES CAUGHT TESTED SCORE MU/lOOg

SERRANIDAE Cephalopholis argus 7.8.84 Flesh N.D. Viscera 3.33 Cephalopholis urodelus 7.8.84 Flesh N.D. Epinephelus megachir 7.8.84 Flesh N.D.

MURAENIDAE Gymnothorax javanicus 7.8.84 Flesh N.D.

LABRIDAE Cheilinus rhodochrous 7.8.84 Flesh N.D Cheilinus digramma 7.8.84 Flesh N.D Epi bulus insidiator 7.8.84 Flesh N.D

MULLIDAE Parupeneus bifasciatus 7.8.84 Flesh N.D.