FISHERY BULLETIN: VOL. 72, NO. 4 



Figure 18. — Worldwide distribution of Nematosce lis tenella based on mid- water trawls. (Broken lines represent approximate bound- 

 aries of distribution of the species based on literature records and present evidence.) 



tribution of many zooplankton species into four 

 types on the basis of their association with water 

 masses. They are: 1) species that show patterns of 

 distribution whose boundaries are almost identi- 

 cal with the boundaries of the physical water 

 masses; 2) species which have areas of highest 

 levels of abundance within a water mass, but 

 whose boundaries extend somewhat beyond the 

 boundary of the water mass; 3) species that have 

 distributions throughout several water masses; 

 and 4) species having limited distributions in 

 parts of some water masses. Nematoscelis gracilis 

 and N. atlantica fall in the first category, A'^. 

 megalops in the second, and N. tenella and A^. 

 microps in the third. Nematoscelis difficilis is re- 

 stricted to the North Pacific transition zone 

 whereas N. megalops is distributed in the central, 

 transitional, and subarctic water masses of the 

 Atlantic and in the southern transitional zones of 

 the Indian and Pacific oceans. 



ACKNOWLEDGMENTS 



The work was supported in part by National 

 Science Foundation Grant GA-31783 and in part 

 by the Marine Life Research Program, the Scripps 

 Institution of Oceanography's component of the 

 California Cooperative Oceanic Fisheries Inves- 

 tigations, a project sponsored by the Marine Re- 



search Committee of the State of California. I wish 

 to thank E. Brinton, M. M. Mulhn, B. Taft, and P. 

 Dayton for their comments on the manuscript. I 

 am specially grateful to E. Brinton for his constant 

 encouragement and guidance during the course of 

 this research. 



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1960. Bemerkungen zu meereskundlichen Beobachtungen 

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