comprised 25 to 75% of the total contents. Longley and Hildebrand 

 (1941) found this species to be almost entirely herbivorous with 

 stomach contents holding 2/3 to 3/4 foreign material, and Beebee 

 and Tee-Van (1928) described stomach contents for this species as 

 "unidentifiable vegetable matter and animal matter." 



Acanthurus coeruleus (Bloch and Schneider) . Blue Tang 



Adults and the bright yellow young of this species are common on 

 reefs in Lameshur Bay. Juveniles were seen around experimental 

 cages , isolated rocks , and occasionally among dense stands of 

 mixed algae on the algal plain almost to the limit of attached 

 vegetation (150 to 180 m seaward) . Adults were observed as much 

 as 35 m from the reef, grazing on the algal plain. On two occasions, 

 adults were seen, immobile, in hollows (but exposed) in the reef 

 at night. By day, A. coeruleus traveled in groups of 4 to 6 , and 

 frequently accompanied A. bahianus or A. chirurgus , together with 

 one or more species of parrotfishes and several spotted goatfishes. 



During feeding trials, A. coeruleus took samples of the sea grass, 

 Syringodium , and the algae Lobophora , Caulerpa cupressoides and 

 Halimeda in eras sat a from assortments including 9 to 15 plant species. 

 Several individuals were usually present during the day, grazing 

 on the fine turf of filamentous plants growing on the surface of 

 the habitat. On the plain species of Udotea appeared to be the 

 principal food taken, but A. coeruleus was also observed feeding 

 upon Lobophora , Dictyot a, and frequently browsed on filamentous 

 species on coral heads and rocks. 



Randall (1967) examined stomach contents of 27 specimens and found 

 algae and detritus to comprise 92.8% of the diet, including 16 

 filamentous, 3 calcareous, 6 fleshy, and 5 leafy species, plus 

 diatoms and 6.8% of the sea grasses, Syringodium and Halophila . 

 Randall, as well as Longley, Schmitt, and Taylor (1925) found 

 little foreign matter mixed with the algal food of this species, 

 in contrast to sand and gravel that was common in the gizzard- 

 like stomachs of A. chirurgus and A. bahianus . No striking 

 differences in the food habits among the three species were observed 

 during this study, however, except that A. coeruleus was more 

 frequently seen on the reefs, browsing on fine algae attached to 

 hard surfaces , and was less common than the other surgeonf ishes on 

 the algal plain. 



Balistidae. Triggerf ishes 



Balistids are common reef fishes with small mouths and powerful jaws, 

 typically carnivorous , but there are several plant-eating species . 

 One West Indian triggerf ish, Melichthys niger , that reportedly 

 shows a preference for plant food. (Randall, 1967) , was not seen 

 during the study. 



VI-155 



