Positive identification of the species within 

 schools could be made only when fish were 

 caught or when the school could be approached 

 closely enough so that the fish were clearly visi- 

 ble. At times fish were not caught or could not 

 be approached, either because of their behavior 

 or because live-bait fishing was not included in 

 the cruise activities. In such instances it was 

 often possible to identify the species of fish by 

 the action of the associated bird flock. Some 

 error in the numbers of schools of different 

 species may be attributed to this method of iden- 

 tification; however, Royce and Otsu (1955) stated 



that identification based on this method was 

 "remarkably accurate." 



During the early 1950's observations were 

 recorded on a variety of forms. In 1954 special 

 log forms (fig. 2) were introduced to simplify 

 recording the various items of information de- 

 sired and to increase the uniformity of obser- 

 vations made on different cruises. A second 

 form (fig. 3), designed to facilitate the transfer 

 of data to IBM punched cards, replaced the 1954 

 version in 1961. 



M/V_ 



OCCURRENCE OF TUNA SCHOOLS, BIRDS, AND AQUATIC MAMMALS 



Noon 

 Cruise Date Position 



B6.1.1 



JEK 4/1/54 



Figure 2. -Log used to record visual observations of tuna schools, birds, and aquatic 

 mammals , 1954-60 



