siifficient speed in the corxfmed quarters to catch them. The tunas 

 accepted dead baitfishj, but only when very hungry^ and then_, with 

 apparent reluctance,, They also fedj with apparent reluctancsj on 

 marlin (Makaira laazara ) flesh after the supply of tuna flesh had been 

 exhausted., The fish in the tank were not fed squid (used in the exper- 

 iments) although this is one of the food items which they will eat 

 when in their normal, habitat (Welsh 1950) o 



The following substances were prepared and introduced to the tank 

 in a manner v\rhich will be described later s I— -baitfish watery 11— 

 baitfish preparations 5, III— squid preparations . IV-=-tuna flesh prepa- 

 rationS;j V—aoparagine and dol^asparagine soluticris,, and VI— =copper 

 acetate solutions o 



The baitfish water consisted of 3 liters of standing seawater in 

 which 50 baitfish had been living for 3 hours,. This "conditioned" 

 water vras used as a test substance o 



The baitfish, squid, and tuna flesh preparations were all made 

 in a similar manner o A quantity (to be reported under each experi- 

 ment) of the substance was quickly mashed m a blender and the mash 

 was extracted m the refrigerator for 3 hours with twice its weight 

 of distilled watero This "whole" preparation was used in some exper- 

 iments „ In others, the preparation was first fractioned into "clear" 

 and "murky" extracts before being usedj the preparation was centri- 

 fuged and the supernatant, conparatively clear fltiid was diluted to 

 3 liters with seawater (the clear extract) s the remaining debris was 

 suspended in 3 liters of seawater (the murky extract) Variations 

 of or extensions to the above procedure are described under indivi- 

 dual experiments o The baitfish were freshly caught? the squid were 

 purchased from the fish market m a frozen conditiCii and thawed 

 just before using^' the tuna flesh, from skipjack and yellowfin^, was 

 in some cases from freshly caught and in other cases from frozen 

 fisho Marlin flesh, from frozen fish,, was also used in a few experi- 

 ments included under IVo 



The asparagine and copper acetate were pure chemicals which were 

 dissolved in seawater m various concentrations as indicated in the 

 individual experiments o 



The above substances were introduced to the tank for the most 

 part on the west side at Point A (figo 2)o To eliminate any reactions 

 based on hearingj they were introduced by means of a siphon from a 

 height of about 1 foot, with the rubber tube inlet about 6 inches 

 below the water surface a 



Quantitative raeasiirement of the reaction of the fish posed a 

 difficult problemo Normally the tuna would cruise leisurely around 

 the tank in one direction for a long timeo At first it was thought 



