logical Survey Program) made systematic sea 

 bird observations over 34,384 miles (63,610 km.) 

 for a total of 3,561.1 hours. This report sum- 

 marizes the observations made on these cruises. 

 The outer perimeter of the cruise track 

 bounds about 500,000 square miles (171.2 mil- 

 lion ha.) of which 5,204 square miles (1.78 mil- 

 lion ha.) are land (Hawaii, Maui, Lanai, Molokai, 

 Kahoolawe). Figure 1 indicates the position of 

 the nominal cruise track in the Pacific Ocean. 

 All except two cruises started and ended at 

 Honolulu, Hawaii; one started at Kauai and one 

 at Maui. Cruises were made each month of the 

 study period except August 1964 and from July 

 -to December 1965. No POBSP observer parti- 

 cipated in the cruises of February 1964 or 

 January 1966. Table 1 gives departure and 

 arrival dates of the cruises on which POBSP 

 observers were present. Cruises are referred 

 to in the text by the month of departure. 



150 °w. 



Kauai 



• 



2tf 



Maui 

 Hawaii 



■|^ 



\f 



155° 



Figure 1. — Replicate track in central Pacific 

 Ocean followed during monthly cruises of the 

 Townsend Cromwell . March 196A to June 1965. 

 Dots represent locations of oceanographic 

 stations. 



The study of the distribution of sea birds is 

 an indirect but effective method for studying 

 the distribution of fishes, since this study pro- 

 vides oceanographers with a visible biological 

 link between the oceanographic phenomena, 

 planktonic organisms, and the fishes of the sea. 



Table 1. — Departure and arrival dates, and extent 

 of observations of sea birds on TWZOP cruises 

 of the Townsend Cromwell 



Methods of Observation 



Observations were maintained continuously 

 from sunrise to sunset, with at least one ob- 

 server on watch at all times. The watch was 

 held on the wings of the ship's bridge (eye level 

 7 m. above sea level), which permitted obser- 

 vations covering an arc of 270°. When wind and 

 waves were low or running with the ship, ob- 

 servations were made on the bow from a height 

 of 6 m. Although the arc of observation was 

 wider from the bow, birds could be spotted 

 more readily from the bridge. Bushnell£' 

 7 X 35 extra wide angle (11° field) binoculars 

 were used on all cruises. On 12 cruises two 

 POBSP personnel alternated 2-hour watches; 

 on 3 cruises during which only one POBSP ob- 

 server was present, the ship's crewmember on 

 watch spelled the observer during meal breaks. 

 The POBSP personnel had previous observa- 

 tional experience in the central Pacific ranging 

 from 72 to over 800 hours. Several members 

 of the ship's crew learned to identify birds 



3/ 



— Trade names referred to in this publication 



do not imply endorsement of commercial products. 



