THE NATURE AND EVOLUTION OF THE HAWAIIAN 

 INSHORE FISH FAUNA i 



By William A. Gosline 



University of Hawaii 



Honolulu lit, T. H., U. S. A. 



Introduction 



A very large number of the shallow-water animals of the Hawaiian 

 Islands are endemic, and the area is usually considered a major zoo- 

 geographic subdivision of the great, marine, shallow-water, Indo-West- 

 Pacific region (Ekman, 1953). Among Hawaiian species of inshore 

 fishes estimates of endemism range between approximately 15% (Fowl- 

 er, 1928) and 50% (Jordan and Evermann, 1905). In my opinion 

 the latter figure is about correct. Neither the distinctiveness of the 

 Hawaiian inshore fish fauna nor its derivation from an Indo-West- 

 Pacific stock are in doubt, and these matters will not be discussed here. 

 The purpose of this paper is to present a preliminary analysis of the 

 factors that appear to have brought about the present, status of the 

 Hawaiian shore-fish fauna. It is based on five years of investigation 

 and on collecting trips to Johnston, Wake, and most of the Hawaiian 

 Islands. Nevertheless, present knowledge is insufficient to provide more 

 than leads to the subject, and no help is to be obtained from other 

 components of the Hawaiian shore fauna, for they are more poorly 

 known than the fishes. Consequently the ideas presented here can de- 

 serve no rating higher than that of working hypotheses. 



Geography 



The Hawaiian Islands (Fig. 1) form a long, narrow chain extend- 

 ing for some 1600 miles along a southeast to northwest axis. Havv^aii, 

 at the southern end of the chain is the largest island in the central 

 Pacific, whereas Kure, at the opposite end, is the northernmost coral atoll 

 in the Pacific. The greatest distance between any two islands in the 

 chain is less than 200 miles. For zoogeographic purposes, Johnston 

 Island (Fig. 1), about 450 miles to the south of the central part of 

 the chain, must be considered an outlying component of the Hawaiian 

 faunal area. 



The nearest shallow waters to the north and east are those of the 

 Aleutians and Alaska, somewhat less than 2000 miles away. Between 



^ Contribution No. 49, Hawaii Marine Laboratory in cooperation with the Department of 

 Zoology and Entomology, University of Hawaii. 



347 



