FISHERY BULLETIN: VOL. 78, NO. 2 



divided into five progressive categories from 1 

 (diarrhea, slight weakness, and flexion of the 

 forelimbs) to 5 (death within 48 h). The lack of 

 symptoms was recorded as 0. The tests which re- 

 sulted in a reaction of 4 or 5 were repeated on other 

 mongooses if sufficient material was available. 

 Also any questionable or unexpected tests were 

 repeated. 



Two tests were run on most of the fishes, one 

 based on the feeding of liver or liver and viscera to 

 the mongooses and one on muscle tissue. The liver 

 of a toxic fish invariably gave a stronger reaction 

 than muscle. A reaction of 3 to liver feeding would 

 generally elicit a reaction of 1 with flesh. Helfrich 

 et al. (1968) found liver more than 50 times as 

 toxic as the muscle tissue of L. bohar. The remain- 

 ing viscera are also more toxic than somatic mus- 

 cle. Since the liver alone was often insufficient in 

 mass to provide a meal to a mongoose at 10% body 

 weight, it was usually necessary to combine it 

 with other viscera (generally alimentary tract 

 tissue). 



The level of toxicity reported herein is from the 

 liver-viscera feeding, with the exception of sharks. 

 Shark liver may cause a toxemia from the high 

 level of vitamin A. Furthermore, it was noted that 

 mongooses will either not eat shark liver or will 

 not consume enough to equal 10% of their body 

 weight. Thus the toxicity data on sharks are based 

 on muscle tissue alone. 



Once a mongoose exhibited symptoms of cigua- 

 tera, it was not used again for testing. If it showed 

 no symptoms at all, it was used a second time, but 

 only after a period of at least 1 wk had elapsed. No 

 mongooses were fed potentially toxic fish more 

 than three times even when no symptoms were 

 elicited. The reason for this is the known tendency 

 for ciguatoxin to accumulate in a test animal. 

 Though a fish may cause no illness when eaten, it 

 may still have some toxin at the subsymptomatic 

 level. Eating several such fishes in succession 

 might result in a positive test for the last one, even 

 though there was insufficient toxin to produce ill- 

 ness in a mongoose consuming such a fish for the 

 first time. 



The results of our first sampling of potentially 

 toxic fishes at Enewetak and Bikini did not in- 

 dicate a high level of toxicity. Only the larger 

 individuals of the usual offending species' were 

 poisonous. Most of these species are carnivores, 

 in particular those feeding heavily on fishes 

 (Randall 1958). Therefore, subsequent fishing 

 was concentrated on the larger fishes of these 



species. Because of this selectivity, both for spe- 

 cies and size, more fishing effort was spent per fish 

 caught; however, this meant less effort expended 

 later in useless testing. 



Prior to the present study, information on the 

 food habits of ciguatoxic fishes was insufficient for 

 most species. When a trained marine biologist 

 familiar with the Marshallese marine biota was 

 present, an analysis was made of the stomach con- 

 tents of the fishes that were caught. Since cigua- 

 toxin is known to pass through food chains to the 

 larger fishes, where it is concentrated, analyses 

 of the stomach contents of these fishes are needed 

 for an understanding of the feeding inter- 

 relationships. 



Some previously unpublished stomach-content 



Table l. — Summary of mongoose feeding tests (liver- viscera, 

 sharks excepted) of fishes collected at Enewetak (0 = nontoxic; 

 5 = death of test animal). 



Intensity of reaction 



Species 



Nebrius ferrugineus 



Carcharhinus albimarginatus 



C. amblyrhynchos 



C galapagensis 



C. Iimbatus 



Galeocerdo cuvier 



Triaenodon obesus 



Taeniura melanospilos 



Lycodontis javanicus 



Adioryx spinifer 



Sphyraena barracuda 



Cephalophalis argus 



Epinephelus fuscoguttatus 



E. hoedtii 



E. maculatus 



E. microdon 



£. socialis 



E. tauvina 



Plectropomus leopardus 



P. melanoleucus 



P. truncatus 



Variola louti 



Aprion virescens 



Lutjanus bohar 



L. fulvus 



L. gibbus 



L. monostigmus 



Macolor niger 



Lethrinus amboinensis 



L kallopterus 



L. miniatus 



L. xanthochilus 



Monotaxis grandoculis 



Kyphosus cinerascens 



Caranx ignobilis 



C. lugubris 



C. melampygus 



C. sexfasciatus 



Gymnosarda unicolor 



Cheilinus undulatus 



Coris aygula 



Epibulus insldiator 



Hipposcarus harid 



Scarus gibbus 



S. rubroviolaceus 



Acanthurus xanthopterus 



Balistoides viridescens 



2 



4 



11 



1 



2 

 8 

 1 



6 

 3 

 2 

 2 

 6 

 8 

 8 

 2 

 4 

 12 



13 



8 



56 



2 



21 



1 



23 



24 



14 



6 



2 



4 



1 



3 



11 



24 



2 



7 



6 



4 



5 



3 



18 



3 



2 



1 



4 



1 

 22 



2 1 



3 



4 1 



1 



8 13 



1 



8 4 



1 



1 



2 



1 



11 5 



5 2 

 1 1 

 2 



Totals 



346 



74 



53 37 



11 



204 



