Visitors are species whose members live in other habitats and only 

 occasionally visit the reef. Such species may be important to the 

 economy of the reef as predators, prey, or competitors but they are 

 not consistently represented by the same individuals. An outstanding 

 example of an important visitor species is the yellowtail Ocyurus 

 chrysurus . One or more individuals of this predator were often at 

 the reef but they were of different sizes and therefore not the same 

 individual. Gooding and Magnusen (1967) distinguished between species 

 that visit a habitat and remain there for a short while and those that 

 pass through without being influenced by the habitat. We have called 

 the later transients and because they do not play important roles in 

 the reef economy we have excluded them from all standing crop calcu- 

 lations. On observation reef 54 species appeared to be residents, 

 15 were visitors and 4 were transients. 



The patterns of space utilization among fishes are generally related 

 to their modes of living and particularly to their feeding adaptations. 

 Herbivores such as surgeon fishes (Acanthuridae) range over wide areas 

 in small groups. Except for three juvenile Acanthurus coeruleus they 

 were transients at the observation reef. Pomacentrus planifrons , 

 however, is also herbivorous and yet strongly territorial. Apparently 

 the reproductive pattern of egg guarding dominates even when the fish 

 are not actively breeding. Chromis cyanea and C. multilineata are 

 plankton croppers. They feed by chasing down individual zooplankters 

 over the reef and they feed constantly during daylight hours. Large 

 resident carnivores such as Petrometopon cruentatum spend much time 

 hovering near the bottom or being groomed by parasite pickers but were 

 rarely observed actually feeding. Wrasses (Labridae) feed on small 

 invertebrates and spend an intermediate amount of time hunting or 

 feeding. Parasite cleaners ( Gobiosoma evelynae . Ho lac an thus ciliaris 

 juveniles) were at work almost constantly during daylight hours. 

 Gnatholepis thompsoni , a goby that feeds on arenicolous small 

 invertebrates seemed to feed at irregular intervals. 



General adaptations to broad classes of food organisms determine 

 where and on what the species can feed. The presence of similar and 

 hence potentially competing species refines the pattern, sometimes 

 dictating specific areas of feeding and sometimes influencing the 

 species preyed upon. 



While some species such as Halichoeres garnoti feed wherever the 

 opportunity arises, most species had special feeding areas either 

 within the reef, in midwater above the reef or over adjacent sandy 

 areas well away from the reef structure. These are listed in 

 table 1, column 5. The size of the area covered during the feeding 

 periods also varied with the species. The goby Quisquilius hipoliti 

 was never observed to move more than 10 cms from its home hole and . 

 even less movement was displayed by the blenny Acanthemblemaria 



VI-266 



