1962-63 

 HIGHLIGHTS 



During 1962-63^^ the Biological Laboratory, Honolulu, 

 made significant new findings in the fields of tuna behavior, the 

 oceanography of the trade-wind zone, the ecology of the skip- 

 jack and albacore, subpopulations of skipjack and bigeye tuna 

 and Pacific-wide and Hawaiian Island oceanography--studies 

 that are outgrowths of earlier exploratory investigations. In 

 addition, the Laboratory participated in a survey of the fishery 

 resources of the Indian Ocean. Our entire program was 

 greatly facilitated by the completion of our new vessel, the 

 Townsend Cromwell , one of the most modern ships in the 

 Nation's oceanographic fleet. 



Defining the sensory capabilities of the tunas received 

 considerable effort in the studies of fish behavior at the Lab- 

 oratory. Visual acuity curves were calculated for the little 

 tunny and skipjack tuna and a study was started to determine 

 the range of frequencies heard by the yellowfin. Direct under- 

 water observations of behavioral and ecological interactions 

 in animal communities that congregate under floating objects 

 were made from a viewing chamber constructed beneath a raft. 

 Studies that resulted in the description and classification of 

 behavior patterns in the Pacific bonito also resulted in the 

 first known observation of the courtship behavior of one of the 

 scombrids, the family of fishes that includes bonito, tuna, and 

 mackerel. 



We have continued to take temperature and salinity readings 

 at Koko Head and are attempting to correlate these, along with 

 other information, with the presence or absence of skipjack in 

 Hawaiian waters. This investigation is a part of a broader 

 program in the oceanography of the trade-wind zone. Our 

 present studies have led to hypotheses regarding the processes 

 which determine the oceanographic climate in the tropical 

 central Pacific. These hypotheses will be evaluated as our 

 studies continue and expand into the field phase. 



Studies were intensified on the skipjack and its relation- 

 ship to the environment, and we think we are beginning to 

 unravel some of the complexities associated with this species. 

 Serological studies of skipjack blood samples collected from 



1/ 



This report covers the period July 1962 to December 1963. 



