The Chaetognath Fauna off Peru in 1941 1 
Robert Bieri 2 
El Nino and the ''Callao painter” of the 
Peruvian Coast have attained a classic stature 
in the annals of oceanography. The catas- 
trophic effect of this phenomenon on the 
marine life of Peru is well known. The less 
devastating El Aguaje (literally strong cur- 
rent or rising tide) is not as notorious, but is 
nevertheless of considerable interest because 
it is a more general phenomenon, occurring 
off California, west Africa, and elsewhere. 
Following the terminology of Sverdrup, 
Johnson, and Fleming (1942), El Nino is used 
in this paper to designate the intrusion south 
along the Peru coast of warm water less saline 
than the general surface water of the Peru 
current. In years of unusually heavy penetra- 
tion of this water to the south the rainfall on 
the normally dry Peruvian coast is very great. 
El Aguaje refers to the intrusion to the coast 
of warm, relatively more saline water of 
oceanic origin from the west. This is fre- 
quently accompanied by minor red tides but 
does not bring heavy rainfall as does El Nino. 
Such phenomena are not only of great eco- 
nomic importance due to the destruction of 
marine life, but also are of considerable scien- 
tific interest because they transport pelagic 
communities great distances from their nor- 
mal ranges. Despite this, the precise effects 
of such occurrences on the quality and quan- 
tity of the local fauna are very poorly known. 
The following discussion describes in some 
detail the distribution of 15 species of Chaeto- 
gnatha in the surface water of the Peru coastal 
current in 1941, in the hope that it will serve 
as a basis for comparison with future work 
in the region and will allow a better evaluation 
1 Contribution from the Lamont Geological Ob- 
servatory, No. 243, Biology Program 8. Manuscript 
received April 23, 1956. 
2 Lamont Geological Observatory, Columbia Uni- 
versity, Palisades, New York. 
of the effects of these disturbances on the 
local fauna. 
ACKNOWLEDGMENTS 
It is a pleasure to thank Dr. Thomas E. 
Bowman of the United States National Mu- 
seum for bringing the existence of the 1941 
samples to the attention of the author and 
for his help in collecting data concerning the 
net tows. The samples were examined at the 
National Museum and the use of its facilities 
and equipment is gratefully acknowledged. 
Thanks are also due the Scripps Institution 
of Oceanography for the use of its facilities 
in examining the 1952 Shellback Expedition 
samples. Preparation of the manuscript for 
publication and examination of the National 
Museum material was partially supported by 
a Rockefeller Foundation Grant (RF 54087) to 
Lamont Geological Observatory, Columbia 
University. 
PREVIOUS WORK 
Our meager knowledge of the Chaetognatha 
in the southeast Pacific comes from a report 
by Baldasseroni (1915) who listed three spe- 
cies, Sagitta enflata , S. lyra , and S. serratodentata 
from a single station off Chile. The reports 
of Grey (1931) and Rose (1953) give some 
idea of the fauna far to the west in the central 
south Pacific. 
The physical characteristics of the region 
are known chiefly from papers by Schott 
(1931), Gunther (1935), and a review of these 
and other data by Sverdrup, et al. (1942). 
Schweigger (1940) describes some of the 
physical and biological features present off 
the Peru coast in 1939- Sears (1954) gives an 
extensive list of literature dealing with the 
Peruvian coastal region. Fleming (1940), 
Schaefer (1954), Bowman (1955), Juhl (1955), 
255 
