Balis tes vetula (Linnaeus). Queen Triggerf ish. 



Queen triggerf Ishes were often observed on the main reef, and were 

 commonly seen on the algal plain, rarely In company with a group 

 of mixed grazing fishes, but usually solitary. Once, four B^. vetula 

 were seen grazing close together on the algal plain, but they behaved 

 as Individuals, without group organization. 



Single fishes were commonly observed during the day as much as 35 m 

 from the reef, but range to at least 100 m distant, as was shown by 

 the occurrence of three queen triggerf ishes Inside experimental 

 cage 2 along transect I. They apparently slipped under the side 

 of the cage, and could move in or out at will, although the edges 

 of the cages were in firm contact with the substrate. On July 9 

 at 1830 hours, all three triggerf Ishes were inside the cage, one 

 about 35 cm, the second about 30 cm and the last 20 cm, standard 

 length. With them were two spotted goatf ishes, and hovering over 

 the cage was a barracuda approximately one meter long. The same 

 scene was present at 1500 hours on July 10: the cage intended to 

 exclude grazers held three triggerf ishes , two goatf ishes, and a 

 school of small snappers, and on the top was parked a barracuda. 



The cage was examined frequently thereafter, day and night, and 

 during the next ten days, at least one, and sometimes all three 

 triggerf ishes (apparently the same individuals) were present, 

 sometimes in company with one or more goatflshes. A barracuda 

 was often seen during the daylight observations, but was not 

 present at night. The last observations were made on July 18. 

 At midday, all three triggerf ishes were in the cage; at 2330 hours, 

 the largest was absent. 



Several queen triggerfishes were observed repeatedly returning to 

 a selected site for the night. One small individual occupied a rock 

 limip inhabited principally by bicolor damselfishes . It was seen 

 emerging from the same crevice several mornings within a minute or 

 two of 0545 hours, and returning at dusk. 



One large rock on a north-south transect line approximately 100 m 

 north of the habitat was occupied at night by a triggerfish about 

 20 cm long, S.L. It was first observed at dusk, 1920 hours, on 

 July 9. A small grouper was in the desired crevice, and was 

 quickly driven out by the triggerfish. The triggerfish then circled 

 the rock, lowered near the entrance, swam away a few feet, returned, 

 hovered near the entrance, again rose above the rock, lowered, then 

 deftly, quickly, ducked into the crevice and wedged there. The same 



Vl-156 



