migrates northward from Chile to Peru during the (northern) summer, and 

 that they move off into unknown spawning grounds during the (northern) 

 winter. 



Along with the direct examination of billfishes, plankton samples were 

 taken for a study of life histories and in order to determine the general 

 nature of the biological conditions of the waters from Chile to Ecuador. 

 Physical measurements were made of the surface and underlying waters in 

 order to obtain a preliminary idea of the desirable objectives for future 

 hydrographic work. The ultimate purpose of this is to determine the man- 

 ner in which physical oceanographic conditions such as currents, wind 

 drifts, upwellings and associated temperature and salinity change, affect the 

 biological content of the waters and consequently, the migrations, feeding 

 habits and distribution of the billfishes. 



The plankton samples were rich, particularly at the more offshore sta- 

 tions, but were disappointing in the comparative absence of young or larval 

 fishes. Since one of the objectives of the expedition was to obtain material 

 for life history studies, it is believed that future work of the expedition 

 should allow for plankton collections in December and January. Since many 

 fishes of the northern hemisphere spawn in early summer, there is reason 

 to believe that the same may be true of the southern hemisphere. This was 

 borne out by the gonad examinations. 



Since the commercial fisheries of the entire coast include the billfishes 

 and since commercial fisheries are, in certain ways, very important indices 

 of organic productivity, a general study was also made of commercial sea 

 fishery operations in Chile, Peru and Ecuador. A general account of this 

 is given in this report with observations on the vessels, gear and methods 

 employed. From this it appears that further information on the hydro- 

 graphic conditions could be of value both in developing the fisheries and 

 in ensuring wise control and management of these resources. An experi- 

 mental longline operation was carried out in Peru with the help of the 

 Wilbur-Ellis Company and under the supervision of Mr. Donald Bates of 

 that company. 



Preliminary examinations of the hydrographic data suggests that the 

 Peru Current extends north as far as Isla La Plata, Ecuador, as a sub- 

 surface current, overlain by a southward drift of warmer waters from the 

 equatorial countercurrent and Panama Current complex. The surface 

 boundary between the Peru Current and the Equatorial countercurrent 

 was located somewhat north of Cabo Blanco and the warm branch of the 

 eddy, first observed by Gunther off Arica, was found to extend as far as 

 Iquique and south. 



The present report is of a preliminary nature and much of the data col- 

 lected still remains to be analyzed. It is therefore necessary to point out 



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