Page 



Extracts of tissues other than flesh 32 



Cajinery by-products: preservation. , 33 



Response to chemical compounds and miscellaneous 



materials 34 



Attempts at isolation and identification of the 



attractant(s) 37 



Summary and discussion 57 



General 57 



Nature of the attractive substance 58 



Preservation of the attractant 59 



Possibility of conditioning of the fish 59 



Literature cited,. 62 



Part II: Response of tuna to visual and visual-chemical 



stimuli 63 



Methods 63 



Response under control and experimental conditions 67 



Pattern of response 67 



School entrances 70 



Percentage of Tinme in Area 70 



Fish-seconds in area 71 



Speed of swimming , 72 



Feeding activitv 73 



Response to lures of different colors 74 



SuiTii-nary 76 



Appendix: A summary of experiments on chemical stimulation 



conducted in tank and pond 77 



