KKrl RE 2. Eve»ifehl [ilavs a significant role in lht> behav- 

 ior of tunas. The ^^tear*'' in the eve of this skipjack is an 

 artifact; it is u drop of water that remained when the fish 

 u;ts taken fri»iti the lank for photography. 



The Gilbert's arrival is the signal for a crane operator to 

 stand by. Fishery scientists fit a bridle to the "bathtub" 

 tanks. One at a time, the tanks are lifted from the deck and 

 taken to the 24-foot plastic swimming pools that are part 

 of the Laboratory's complex for behavioral research. There 

 the lids are unbolted. The crane lifts the containers and 

 then lowers them into the sea water pools. Fishery scientists 

 carefully tip the containers to let their living cargo swim 

 free. 



Such painstaking methods have had impressive results: 

 the Kewalo Basin facility often has as many as 60 or more 

 tunas waiting their turn for behavior studies. Thus this 

 Laboratory has become the only one in the world where 

 living tunas are regularly collected and held for study. The 

 procedure for handling the fish was worked out by biologist 

 Eugene L. Nakamura. One of the technological triumphs 

 of the Laboratory has been its ability to keep skipjack tuna 

 alive for several months. Prior to our improved handling 

 methods, the skipjack usually dashed themselves to death. 

 Now specimens -have been kept alive as long as 6 months 

 in the Laboratory's tanks. 



Only since Nakamura perfected his methods of handling 

 have he and other behavioral scientists in the Laboratory 

 been able to conduct controlled experiments with tunas. 

 Already several scientific papers have been prepared, each 

 of them revealing previously unknown facets of behavior. 

 Currently underway are studies of how well the fish see and 

 hear and how they are able to maintain swimming depth. 

 From the broad base of such information may come new 

 and unconventional methods of catching tunas for commer- 

 cial purposes. 



How Well Do Tunas See".' 



How well tunas see has obvious implications for the 



fishery. Experiments in the lucent waters of the central 



Pacific a few years years ago proved it well-nigh impossible 



to catch skipjack tuna in any numliers with a monofilament 



