802 EIGHTH PACIFIC SCIENCE CONGRESS 



ditions were repeatedly subject to invasions of the Equatorial Counter- 

 current with some of its consequences but never in such a degree as 

 reported for the summer of 1925. The author presented to the Sixth 

 Pacific Science Congress in 1939 a paper regarding the hydrographic 

 anomalies observed in that same year and by coincidence he wishes to 

 relate to the same Congress to be held in November 1953 about other, 

 and perhaps even greater, disturbances of the normal conditions in the 

 summer of 1953. 



It must be said that nearly all reports contained in the oceano- 

 graphic literature about destructive biological changes in the Peruvian 

 Current are extremely exaggerated and generalize the extraordinary 

 events which have been observed only twice during the last 62 years. 

 Some abnormal situations, marked by the emigration of the guano-birds, 

 are recorded for November-December 1912, March 1917, March and 

 June 1923, but only for 1923 is the death in greater extension of fishes 

 mentioned (Lavalle 1917, 1924). Later perturbances occurred in 1932, 

 1939, 1941, 1951 and the last one just recently in 1953, this, however, 

 without any biological consequences. These are characterized by the 

 emigration of almost all or at least an appreciable part of the guano- 

 birds which occupy the small islands off the Peruvian shores. Nothing 

 has been heard or seen since 1938 of a widespread mortality of fish, 

 except some rare occurrences when fishes still alive were washed ashore 

 (1941), perhaps poisoned or suffocated by lack of oxygen. However, 

 oceanographic perturbances have taken place in all these years and in 

 a lesser degree also in 1949. If it were not for the behavior of the 

 guano-birds, which are carefully watched in view of their importance 

 as producers of guano, one source of Peru's great wealth, the abnormal 

 conditions in the sea would not be noticed. Abnormalities can only 

 be detected by careful hydrographic observations. 



It is not the intention of this paper to enter into details about the 

 biological changes which take place in years of greater hydrographic 

 perturbances, but only to show the abnormal features of the summer 

 of 1953 in comparison with those of some other years, and to discuss 

 some hydrographic phenomena connected with these disturbances. 



All the data used for the original charts reproduced herewith are 

 based in their greater part on observations made by the author on board 

 ships of the Guano-Company (Compania Administradora del Guano, 

 Lima), in sailing ships in 1939 and 1941 and complemented by data 

 obtained from merchant vessels navigating along the Peruvian Coast. 

 The data collected are kept in special oceanographic archives of that 

 same Company. It must be stated here that the great merit of the 

 Guano Company, besides the absolute and well planned protection 



