Bjerknes, J. 1961. "El Nino" study based on analysis 

 of ocean surface temperatures 1935 to 1957. Inter- 

 Am. Trop. Tuna Comm. Bull. 5:219-303. 



Discussed the seasonal variation reflected in 

 winds and sea surface temperatures as related 

 to atmospheric and oceanographic changes, all 

 pertaining to the development of El Nino. 

 Compared 1935 to 1957 sea surface tempera- 

 tures with data in the Hydrographic Office 

 Atlas and presented evidence of a general 

 warming trend in the open sea area south of 

 the equator, a cooler tendency in coastal and 

 equatorial upwelling zones. El Nino results 

 from ocean-wide weakening of northern trade 

 winds, permitting abnormally large volumes of 

 warm water to accumulate in the eastern 

 tropical Pacific. A weakness in the southern 

 trade winds plus a possible south equatorial 

 countercur rent add to the above phenomena. 



KEY WORDS: winds, currents, season, pres- 

 sure, upwelling, thermocline depths, El Nino. 



Blackburn, M. 1959. Scripps Tuna Oceanography Re- 

 search (STOR) Program - Quarterly Progress Report 

 No. 6. Univ. Calif. SIO Ref . (59-22), 17 p. 



Comparison of tuna catches and zooplankton 

 volumes off Baja California. 



KEY WORDS: tuna, feed. 



Blackburn, M. 1959. Analysis of tuna availability in 

 relation to oceanographic variables. _In M. Black- 

 burn (editor), Scripps Tuna Oceanographic Research 

 (STOR) Program - Quarterly Progress Report No. 7. 

 Univ. Calif. SIO Ref. 59-31:4, 8. 



Comparison of tuna catches with abundance of 

 zooplankton and micronekton. 



KEY WORDS: tuna, feed. 



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