A NEW APPROACH TO THE DISTRIBUTION OF FISHES 

 IN THE INDO-WEST PACIFIC AREA 



By Leonard P. Schultz 



Smithsonian Institution 

 United States National Mv^eum, Washington 25, D.C., U.S.A. 



Much has been written on the distribution of marine fishes of the 

 Indian and Pacific Oceans. Roughly ichthyologists classify the marine 

 ecological habits into three categories, shore, pelagic, and deep-sea. Al- 

 though these groupings are useful there is a considerable overlap be- 

 tween the zones and their limits vary in different seas. 



Shore fishes are those that occur over the continental shelf or along 

 the coastal areas, and around the shores of islands; as adults, normally 

 not far out to sea, and usually in depths shallower than 600 feet. Most 

 typical deep-sea fishes live in the stratified subsurface layers of the sea 

 and because of the uniformity of temperature and salinity in these 

 areas, they may have an almost world-wide distribution. 



The marine shore fishes may be divided into two main regions: 

 tropical and temperate. The tropical shore fauna extends around the 

 world but is definitely restricted by temperature. The temperate fauna 

 may be subdivided into: North Pacific, North Atlantic and Temperate 

 South Pacific. 



The circumtropical marine shore fauna may be divided into two 

 main regions: Indo-West-Pacific and West-Atlantic-East Pacific. 



The richest marine shore fauna of the world is that of the tropical 

 Indo-West-Pacific containing, with but few exceptions, representatives 

 of all known living tropical shallow-water marine fish families and a 

 very high percentage of all the genera occurring in other tropical 

 regions. 



The geographical boundaries of the tropical Indo-West-Pacific 

 shore fauna are in general the region from the head of the Red Sea 

 southward along the African coast to Natal, thence eastward including 

 island groups and coastal regions of Southern Asia, northward to the 

 Ryukyu Islands and Southern Japan, southward to Northern Australia, 

 the Great Barrier Reef and New Caledonia, thence eastward to the Tua- 

 motu Islands and Easter Island, northwestward to include the Hawaiian 

 Islands. Although the boundaries of this region are ill-defined the fauna 

 is mostly restricted to coral reefs. 



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