Extracts of skipjack ovaries (No„ 3) and yellowfin testes 

 (NoSo 4p 17) were not attractiveo However 5 whole extracts were used 

 eind the fish may have been frightened by the murky cloud which they 

 produced in the water,, 



Unfiltered extracts of yellowfin skin (NOo 24) and tunny 

 skin (Noo 29) also formed a dark cloud in the water and were more 

 repellent than attractive^ An almost clear centrifuged extract of skip^ 

 jack skin (Noo 48^ gave a weak positive responseo 



It appears that the attractantis present not only in tuna 

 flesh;, but also m other parts of the fisho Again„ however^ it is 

 difficult to come to any firm conclusion as to the relative strength of 

 the response 5 and thus the relative concentration of the attractant in 

 the various partSo In general the viscera extracts appeared to be at 

 least as attractive as the flesh extractSp and possibly slightly more 

 attractivCo In two series of esjperinnents designed to compare ex^ 

 tracts of bloody liver, skin, and flesh (NoSc 23 to 26„ Nos, 27 to 30), 

 extracts of blood and liver appeared to be more attractive than ex= 

 tracts of flesho and extracts of skin appeared to be less attractiveo 



C anne ryJBygr oductsj Preserv ation 



Good (XX) responses were obtained with extracts of tuna 

 fish mealp both boiled Wo, 119^ and not boiled (No,, 120) during ex- 

 traction^ Excellent responses jXXX> were obtained with tuna sticks 

 water both by itself (NOo 217) or mixed with fluorescein dye to trace 

 its dispersion m the pond (Noo 222'o 



"Condensed herring solubles^ " a product derived from the 

 stickwater of a herring reduction plant (B, C„ Packers^ Ltdo ) was not 

 sensed by the fish (Nos, 328 and 329U 



Several experiments were run on skipjack viscera 

 preparations submitted by Hawaiian Tuna Packers, Ltdo with excel- 

 lent results (XX to XXXXt, In all preparations the viscera from the 

 cannery were first ground in a meat grindero In some they were pre = 

 served in 2- or 3-percent sulphur dioxide and self-digested^ produc* 

 ing a particulate portion which settled to the bottom of the container 

 and a supernatant dirk brown liquid (NoSo 219g 221^ 290^ etCc,)o In 

 others, the ground \nscera were steamed at 20 pounds pressure and 

 preserved in 3 -percent phosphoric acid; again producing a solid and 

 a supernatant yellow liquid 'No, ZZO)^, A ground viscera preparation 

 preserved in 2-percent sodium bisulphite ^nd digested with pepsin 

 gave little evidence of attraction in three tests (NoSo 258^ 260^ and 

 263II0 Apparently loss of attraction was due to something associated 



33 



