Table 2, — Summary of the response of tiinny to pieces of cooked macaroni 

 and strips of agar In several experiments 



The best response, with 96 pei-cent of the lures being eaten, was ob- 

 tained with agar strips cooked in concentrated extract. As they assumed a brown- 

 ish color, they may have been visually as v/ell as chemically more attractive than 

 plain colorless agar. The addition of aluminum did not seem to increase the at- 

 tractiveness of the agar preparations. 



A series of tests wa 

 ences in response to (a) macar 

 coated with aluminum powder, a 

 and Impregnated with al-uminum 

 large quantity used in sea tes 

 The lure preparations were pre 

 time. The pairs of tests were 

 again throughout the afternoon 

 3 and 4. 



s conducted to determine if there were any dlffer- 

 oni cooked in concentrated skipjack extract and 

 nd (b) agar cooked in concentrated skipjack extract 

 powder. In both cases the preparations, part of a 

 ts, were preserved with 1 percent sodium bisulphite, 

 sented alternately to the fish, eight pieces at a 

 repeated several times throughout the morning, and 

 of the same day. The results are shown in tables 



In the morning series (table 3) the tunny ate 69 percent of the macaroni 

 lures and 100 percent of the agar lures. In the afternoon series (table 4) they 

 ate only 10 percent of the macaroni lures but stll] ate 100 percent of the agar 

 lures. It is obvious from the data, and It was still more obvious from observa- 

 tion, that the pond fish showed a decided preference for the agar lures after the 

 first pair of tests. The percentage of macaroni lures which was eaten gradually 

 decreased with successive testing. In the last three oalrs of tests in the after- 

 noon some of the pieces of macaroni were taken into the mouth, but all were re- 

 jected; on the other hand" all agar strips, if seen, were eaten. Apparently a 

 learning process was involved. In general, the overall reaction- (speeding, sur- 

 facing, splashini^, return to area, etc.) was more pronounced with the agar than 

 with the macaroni lures; the difference v/as more noticeable in the morning than In 

 the afternoon tests. 



11 



