Biogeographical Boundaries: The Shapes 

 of Distributions 



R. S. GLOVER 



Oceano graphic Laboratory, Scottish Marine Biological Association, 

 Edinburgh, Scotland 



MANY of you will be familiar with pictures showing distributions 

 of animals and plants which appear to be related sensibly to the 

 distribution of other organisms or of some measured feature of 

 the environment or of some geological character. Such pictures 

 are mostly taken from studies of terrestrial ecology, occasionally 

 from fresh or brackish water or from work at the edges of the 

 sea, from the intertidal zones. But all of us who have worked on 

 marine problems know that there are boundaries in the middle 

 of the ocean which are sometimes as sharply defined as the bound- 

 aries between sea and shore or between wood and meadow. The 

 need for charts of distribution in the open ocean was recognized 

 by the American National Academy of Sciences whose Committee 

 on Oceanography has produced a most enlightened and ambitious 

 series of documents under the general title Oceanography, 1960 to 

 1970. In Chapter 3, on "Ocean Resources" the committee reports 

 that: 



There is a great need for continual, systematic mapping of the oceans. 

 This should show quantitatively, by seasons, the geography of the vari- 

 ous elements composing marine environments .... Its practical applica- 

 tion would be to predict the location of promising fishing areas and the 

 probable abundance of fishery resources therein. 



The Committee referred to "continual biological surveys to 

 measure the ever-changing abundance of exploited fish stocks 

 , . . and map shifts in patterns of distribution." 



Much of the present knowledge of marine biogeography was 



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