WATER MASSES AND CURRENTS OF THE OCEANS 191 



Equator before converging with the Peru Coastal Current. The warm, 

 south-flowing current along the coast is known as "El Nino," and is a 

 regular phenomenon in February and March, but the southern limit lies 

 mostly only a few degrees to the south of the Equator. Occasionally, 

 major disturbances occur that appear to be related to changes in the 

 atmospheric circulation. In disturbed years, such as in 1891 and in 

 1925, the El Nino extends far south along the coast of Peru, occasionally 

 reaching past Callao, in 12°S. According to Schott, the duration of the 

 El Nifio period of 1925 was as follows: 



Off Lobitos lat. 4°20'S Jan. 20-April 6 76 days 



Off Puerto Chicana " 7°40'S Jan. 30- April 2 63 days 



Off Callao " 12°20'S March 12-27 15 days 



Off Pisco " 13°40'S March 16-24 8 days 



These figures show that the warm surface waters of the equatorial area 

 slowly penetrated to the south, but withdrew much more rapidly, because 

 the time interval between the appearance of the warm water off Lobitos 

 and off Pisco was 44 days, whereas the time interval between the disap- 

 pearance of the warm water at the two localities was only 13 days. The 

 surface temperature of the water in March, 1925, was up to 7° above the 

 average, as shown in the following compilation : 



Average temperature Temperature in 



in March March, 1925 



Locality (°C) (°C) 



Lobitos 22.2 27.3 



Puerto Chicana 20.3 26.9 



Callao 19.5 24.8 



Pisco 19.0 22.1 



Details as to the surface salinity are not available, but normally the 

 surface salinity between 5°S and 15°S is above 35.00°/oo, whereas the 

 waters of the El Niiio have a salinity between 33.00 and 34.00°/oo. 



The extreme development of the El Nifio leads to disastrous catas- 

 trophes of both oceanographic and meteorological character. The 

 decrease of the El Nifio temperature toward the south indicates that the 

 waters are mixed with the ordinary cold coastal waters, and during this 

 process the organisms in the coastal current, from plankton to fish, are 

 destroyed on a wholesale scale. Dead fish later cover the beaches, where 

 they decompose and befoul both the air and the coastal waters. So much 

 hydrogen sulphide may be released that the paint of ships is blackened, 

 a phenomenon known as the '^ Callao painter." More serious is the loss 

 of food to the guano birds, many of which die of disease or starvation or 

 leave their nests, so that the young perish, bringing enormous losses to 

 the guano industry. The meteorological phenomena that accompany the 

 El Nino are no less severe. Concurrent with a shift in the currents a 



