FISHERY BULLETIN: VOL. 78, NO. 2 



Starks was created for the species from Mexico. 



Two specimens, 423 and 425 mm SL, 2.7 kg, 

 were obtained from Enewetak for the assay of tox- 

 icity. Neither were toxic. 



Hiatt and Strasburg (1960) examined the 

 stomachs of four specimens from Enewetak, two of 

 which were empty. The other two contained short 

 filaments of algae with much sand, hydroid hy- 

 drocaulus, and wood splinters (probably from 

 grazing on pilings). Jones (1968) classified A. 

 xanthopterus as a grazer on diatoms and detritus 

 in sand patches. That it will take animal food 

 when the opportunity arises was aptly shown by 

 Helfrich and Banner (1963) who used this species 

 to induce ciguatera toxicity by feeding the poison- 

 ous flesh of Lutjanus bohar. 



Ctenochaetus striatus (Quoy and Gaimard) 

 (Figure 49): This surgeonfish is much the most 

 common of the four species of the genus that occur 

 in the Marshall Islands. It is, in fact, one of the 

 most abundant reef fishes throughout the Indo- 

 West Pacific region (though not Hawaii). The 

 genus is named for its comblike teeth which are 

 numerous, slender with expanded incurved tips, 

 and flexible in the jaws. Randall (1955b) has dif- 

 ferentiated C. striatus from the other species by 



having 5-7 denticulations on the expanded distal 

 tips of the upper teeth, the highest average 

 number of dorsal and anal soft rays (modally 29 

 dorsal rays and 26 or 27 anal rays), and a lunate 

 caudal fin. 



Bagnis et al. ( 1968) reported that surgeonfishes 

 ( particularly C. striatus ) are responsible for 65% of 

 the cases of ciguatera in Tahiti. There are three 

 reasons for this: 1) the abundance of C. striatus, 2) 

 its good-eating quality, and 3) the knowledge that 

 the symptoms will be mild if ciguatera is incurred. 



Bagnis (1968) documented the great variation 

 in the symptoms of ciguatera in French Polynesia. 

 He noted that digestive and neurologic symptoms 

 predominated among those patients who had in- 

 gested surgeonfishes. 



Yasumoto et al. (1971) determined that there 

 are two principal toxins in C. striatus, one of which 

 is fat soluble and chromatographically identical 

 with ciguatoxin, and the other is water soluble. 

 The latter was found only in the liver and gut 

 contents. In a few specimens from Tahiti a differ- 

 ent fat-soluble toxin and a different water-soluble 

 toxin were detected. 



In order to determine if more than one toxin is 

 present in C. striatus in the Marshall Islands, 22 

 adult specimens were speared on lagoon reefs of 



Figure 49. — Ctenochaetus striatus, 94 mm SL, Enewetak, Marshall Islands. 



242 



