experiments o It may be concluded trom. this and the four other 

 experiments that baitfish water has no apparent attractive or re- 

 pellent effect o 



Figure 3 also shows the results of a control experiment in 

 which seawater was siphoned in at Ao Again^ there was no notice- 

 able or measurable reaction of significanceo 



iio Baitfish preparations 



In several experiments j, one of two schooling yellowfin was 

 timed in preliminary tests j, on introduction of the clear extract 

 of the baitfish preparationj and on introduction of the marky 

 extract of the baitfish preparationo The results of only one experi- 

 ment are recorded in figure h» in which 1^1 grams of baitfish (wet 

 weight) was usedo 



On introduction of the clear extract^ there appeared to be an 

 increase in cruising speed and an increase in the number of passes g 

 particularly in Tests 10 and lit, The mean decrease in time for 10 

 passes was from 112 o 3 seconds for the preliminary tests to 960 3 

 seconds for the tests with the clear extracts The difference is not 

 statistically significant,,^ 



On introduction of the murky extract there was at first a slight 

 increase and then a considerable decrease in cruising speedo The 

 initial increase might be construed as a reaction to the substance $, 

 but not necessarily as an attraction^ as the nmaber of passes across 

 AB did not increase., 



"Hie other experiments yi&lded even less evidence of attraction 

 to the baitfish preparations o It may be concluded that this sub- 

 staace has either very slight attractive properties or none at alio 



3/ A sin5)le test of the significance of the difference between the 

 ~ mean times is not necessarily informative in experiments of this 

 nature as (i.) during the preliminary timing there may be a gradual 

 decrease in cruising speed as the fish become accustomed to the 

 * presence of the observer ^ and (h) during siphoning j there may be 

 at first no change, then an increase,, and finally a decrease in 

 cruising speed (and number of passes; during the times in irtiich 

 the substance is entering ^he tankg spreading over a small vol- 

 ume of sea water near the inlet, and gradually dispersing in 

 smaller concentration farther and farther from the iaJeto Un- 

 fortunately the data are not sufficiently extensive for more 

 detailed statistical analysis even if a procedure could be designed 

 to handle this con?)lex situationo 



Hi 



