RANDALL: SURVEY OF CIGUATERA AT MARSHALL ISLANDS 



fishes may be poisonous, the toxic organism would 

 most likely be an alga, a fungus, a protozoan, or a 

 bacterium." He added that if it were an alga it 

 must be fine because certain potentially toxic sur- 

 geonfishes are unable to feed on coarse types. Of 

 the algae, he wrote that blue-greens were the most 

 probable source of ciguatoxin. 



Yasumoto et al. (1977), however, have shown 

 that the "likely culprit" of ciguatera is a di- 

 noflagellate which lives attached to dead coral or 

 benthic algae. Though identified initially as a new 

 species of Diplopsalis, it was later shown (Taylor 

 1979) to be a new genus as well. Subsequently, 

 Adachi and Fukuyo (1979) named it Gambierdis- 

 cus toxicus. Although a fat-soluble toxin, later 

 identified as ciguatoxin, was isolated from wild 

 dinoflagellates of this species, this organism pro- 

 duced "... only meager amounts of ciguatoxin, if 

 any,. . ." under culture conditions (Yasumoto et al. 

 1979). 



The author first visited Enewetak in 1967, then 

 in use as the terminus of a missile range by the 

 United States. The resident personnel had been 

 informed of the hazard of ciguatera, and local reef 

 fishes were not served in the mess. In spite of the 

 warning, some cases of ciguatera still occur, espe- 

 cially with the crews on supply ships to the island 

 who sometimes catch and eat fishes, particularly 

 red snapper, Lutjanus bohar, from the vessels be- 

 fore they could be informed of the danger. The 

 most recent case was reported by Roth.'* 



In 1968 six residents of the atoll ate a large 

 reddish brown grouper with small blue spots 

 (probably Plectropomus leopardus) that one of 

 them had caught off the garbage pier at the 

 southwest end of Enewetak Island. They had 

 asked a cook in the mess hall to prepare the fish for 

 a meal. The cook refused, explaining that the 

 species was one which could make them sick. Dis- 

 believing, the men took the fish to their quarters 

 and cooked it themselves. They all contracted 

 ciguatera and were hospitalized (Spillman). 



These cases offish poisoning and the knowledge 

 that the marine environments of both Enewetak 

 and Bikini have indeed been disrupted underlined 

 the need for a survey of ciguatera at the two atolls. 



The survey was supported by the U.S. Energy 



"Robert M. Roth, Capt. USAF, MC, Command Surgeon, Joint 

 Task Group, Enewetak, described the illness (symptoms typical 

 of ciguatera) of Francisco Romolor, age 28, a civilian deckhand 

 on the cargo ship Muskingum, following ingestion of a red snap- 

 per caught in the lagoon (pers. commun. 2 June 1978). 



^Louis C. Spillman, Jr., Chief Medical Officer, Enewetak, pers. 

 commun. 1968. 



Research and Development Administration (now 

 Department of Energy). The field work at 

 Enewetak was based at the Mid-Pacific Marine 

 Laboratory, and the fishing at Bikini was carried 

 out from the RV Liktahur.^ The testing of fishes 

 for ciguatoxin was done at the Hawaii Institute of 

 Marine Biology, University of Hawaii, under the 

 supervision of A. H. Banner. 



Six fishing expeditions of 2 to 4 wk duration 

 were dispatched from Hawaii to Enewetak within 

 the period September 1974-May 1978. There were 

 four fishing cruises to Bikini (fishing periods of 3-7 

 days at the atoll) from December 1974 to July 

 1976. In addition, 12 potentially toxic L. bohar 

 were caught from the Liktanur at the atoll of 

 Rongelap in November 1975. 



Fishes were collected by spearing, hook and 

 line, trolling lures, explosives, and the ichthyocide 

 rotenone. The specimens were held in chests of 

 crushed ice until they were returned either to the 

 Mid-Pacific Marine Laboratory or the Liktanur. 

 They were then measured and weighed, tagged 

 with a metal tag, and a sample taken for testing 

 which included the liver, other viscera, and mus- 

 cle. A data sheet was filled out for each specimen; 

 the upper half of each sheet was used for field data 

 and the lower half to record the testing for toxicity. 

 A chart of the atoll was printed on the back of each 

 data sheet (separate sets of sheets were main- 

 tained for Enewetak and Bikini) so that the local- 

 ity of capture could be recorded. At Enewetak the 

 entire fish was frozen after the sample was taken 

 for testing. Aboard the Liktanur only the samples 

 were retained. The Enewetak specimens, which 

 proved to be highly toxic (rated 4 or 5, see below), 

 were transported frozen to the University of 

 Hawaii for use in biochemical and pharmacologi- 

 cal research on ciguatoxin; the remaining fishes 

 were either discarded or used as bait or chum. 



For the testing, the samples of fish were fed to 

 mongooses (Herpestes mungo) in single meals at 

 10% body weight. The mongoose is a good animal 

 for the bioassay of ciguatoxin (Banner et al. 1960) 

 because it has a symptomology similar to humans 

 suffering from ciguatera, it retains a meal of toxic 

 fishes (in contrast to cats which are prone to re- 

 gurgitate fish when it is very poisonous), and be- 

 cause of its availability in Hawaii (where it is 

 regarded as a pest). The mongoose symptoms were 



«The RV Liktanur is a converted U.S. Navy LCM, 115 ft in 

 length, operated then by the U.S. Energy Research and De- 

 velopment Administration as a research and supply vessel. 



203 



