SPACE RESOURCE SHARING IN A CORAL REEF 

 FISH COMMUNITY 



C. Lavett Smith 



The American Museum of Natural History 



and 



James C. Tyler 



Academy of Natural Sciences of Philadelphia 



ABSTRACT 



Coral reef fish communities are highly diverse assemblages 

 of interacting species. Present observations indicate 

 that the resident species are present in approximately the 

 same numbers over long periods of time although there are 

 probably annual cycles of abundance for each and therefore 

 seasonal changes in relative abundance. Direct observation 

 of a small patch reef during a two week period has revealed 

 patterns of space utilization that are interpreted as 

 mechanisms for avoiding interspecies competition. Seventy- 

 three resident and visitor species were studied. Important 

 aspects of space sharing are: location and type of shelter 

 during inactive periods, timing of activity cycles, home 

 range size, and special behavior patterns such as schooling 

 and territorial defense. It is suggested that intraspecies 

 competition for space may play a major role in maintaining 

 numerical stability within the community. 



INTRODUCTION 



Coral reef habitats support fish communities that are among the most 

 diverse known. Patch reefs only four or five meters across frequently 

 house fifty to one hundred species of small fishes, apparently living 

 together in reasonably stable dynamic equilibria. These communities 

 offer rewarding challenges to ecologists interested in the funda- 

 mental principles that govern the development and maintainence of 

 high diversity communities. With the availability of suitable diving 

 gear and efficient collecting methods these and other shallow marine 

 habitats are now accessible for gathering reliable quantitative data 

 for analysis of community s^tructure. 



OBJECTIVE 



The object of this study has been to examine the space utilization 

 patterns of the fishes of a small patch reef in an effort to learn 

 how these patterns influence the stability of the community. The 

 density of fishes in coral reef habitats as measured by both numbers 

 of species and numbers of individuals suggests that space sharing is 



VI-261 



