The David Starr Jordan departed San Diego February 7 to participate 
in the EASTROPAC Project. The primary objective of the trip was to 
survey the oceanographic environment of physical and biological rela¬ 
tionships between the area of 20°N - 112°W and 20°S - 105°W in an 
attempt to find a better understanding of pelagic tuna resources. 
The ship traveled from San Diego to 12°N - 111°W and then headed 
northeast on a direct line for Manzanilla, Mexico. On l 8 February 
the ship departed Manzanillo and traveled along the coast of Acapulco. 
From Acapulco, stations were resumed on 20 February and the track 
ran southwest to 12°N - 105°W. The ship then proceeded south along 
105°W to 20°S. From this point a northwestern course was taken without 
stations until 10°S - 112°W was reached. The Jordan continued along 
112°W to 20°N, where the study area ended and then returned to San 
Diego on 24 March.- Environmental data were collected at about 20 
mile intervals in all areas between 20 °N and 20 °S except the two areas 
previously mentioned. 
As a visiting scientist aboard the David Starr Jordan, I conducted 
bird, mammal, and fish observations for 43 days while the ship was at 
sea. Excellent cooperation was received from Dr. Longhur.st, the 
scientific crew, Captain Foster, and the ship's crew, in all phases of 
observing and collecting birds throughout the trip. This preliminary 
report summarizes these observations. 
In 40 days, a total of 308*5 hours was spent observing, while the 
ship traveled 35^18 miles. An additional 38 hours of nocturnal obser¬ 
vations were recorded from various points throughout the trip. Obser¬ 
vations were conducted on three additional days but due to the proximity 
to the coast only speciea .accounts and relative abundance of species 
were recorded. 
During diurnal observations 4,020 birds of 4l species were recorded. 
Nocturnally, 175 birds of 8 species were recorded.. Sooty Terns (III 7 ) 
were the most abundant. Leach Storm Petrels (9^8) and Red Phalaropes 
( 137 ) were reg\ilarly seen throughout the trip. Townsend. Shearwater ( 687 ) 
Wedge-tailed Shearwaters (291) and ^ied-footed Boobies (2^3) were present 
in large numbers in restricted areas. The most abundant bird throughout 
the trip in terms of birds per square mile whs Leach Storm Petrel. 
METHODS 
I 
Observations were conducted from sunrise to sunset throughout most 
of the trip. Watches were not held during the noon station which varied 
in length from 2 l/2 to 4 hours. Due to the difference in daily steam¬ 
ing time the most important figure is birds per linear mile per day and 
not total birds per day. 
