To survive in the pond or tank the tuna must become 

 conditioned to feeding on inert, dead rather than motile, living food. 

 After beconming conditioned to feeding on food such as strips of aku 

 flesh, the fish appeared to have little interest in live food such as 

 small baitfish ( Stolephorus and Pranesus) , which at times were 

 present in the pond in fair abundance. On rare occasions they were 

 observed to pursue the baitfish, which usually schooled near the sea- 

 ward gates of the pond, but they would give up when the baitfish re- 

 ceded to a position close to the gates. They were not observed to 

 actually capture any, and usually they ignored them. On the other 

 hand, the tunas would alnnost invariably circle and snap at objects 

 other than food which were thrown or fell accidently on the water 

 surface (leaves, pieces of cellophane, etc.). This response was 

 probably conditioned by the method of feeding. When a person ap- 

 peared at the edge of the pond with a bucket of food, the fish would 

 often see him and gather nearby, waiting for the food to be thrown to 

 them. When it was thrown, they would follow its path and take it 

 immediately it landed on the surface. 



It is possible that they were conditioned to being fed at 

 regular intervals of time (usually 4 p.m. every second day), although 

 they would respond to the presence of both persons and food at any 

 time except immediately after being fed. 



As most of the extracts which were used were not visible 

 to the fish, there is no doubt that the response was through the fish's 

 sense of snnell or taste rather than through its vision. However, there 

 is the question as to whether the fish responded to skipjack flesh ex- 

 tracts because they were being fed pieces of skipjack, or closely- 

 related tunas, as a regular diet. There is evidence that the response 

 was not conditioned by the type of food which was fed. 



Before and during the early experinnents in the tank (to 

 July 18, 1952) the one established tunny was fed a non-tuna diet 

 (squid and baitfish), yet it still responded to extracts of skipjack 

 flesh (NoSo 1, 8, 10) which it had not tasted while in captivity. 

 Following April 25, 1953, the two tunny in the pond were fed exclu- 

 sively on squid, yet eilmost 1 month later. May 19, 1953, they still 

 responded to extracts prepared from skipjack viscera and yellowfin 

 flesh (Nos, 350 to 356). 



The fact that jpositive responses were obtained to extracts 

 of fish other than tuna- -aholehole (Nos. 49, 88, 105), jack (No. 96), 

 and barracuda (No, 98) --while the tunny were still being fed skipjack 

 is also evidence that the response was not conditioned by the species 

 of fish which was being used as food. This, of course, is also 



60 



