drated carrot, dehydrated lettuce, dehydrated 

 s|)iiiac.h. and deliydrated water cress. 



The following analj-sis was sujjplied hy the 

 maker: 



Crude protein, minimum 40 porcpnt 



Crude fat, niiiiinium 3 percent 



Crude fibre, maximum lOperceut 



Artemia nauplii wore jjioduced by placing; tlie 

 (hy eggs in 750 ml. uf sah water (one level table- 

 spoonful per 750 iid.) and incubating them 2 

 (lays at about 24^^ ('. Food was supplied In tanks 

 according to the schedule in table 1. Ail oi the 

 daily food allotment was placed ii\ the tanks at 

 line time. During the early ])art of the experiment 

 some food fell to the bottom of the tanks uneaten; 

 it was sijihoned out before the following day's 

 feeding. When the ])oi)ulations had grown to pre- 

 o.xploitation sizes, all food was consumed. 



T.\Bi,B 1. — Schedule of food siippUed to tanks receiving 

 various diets. The "standard" diet is designated 1.0 



0.5 diet 



1.0 diet 



1.5 diet 



l);iy of 1>>0- .Arte- Fio- Arte- Vvo- Arle- 



wcpli zcn mia Dry zcn mia Dry zcn mia 



Dapli- nau- food KapA- nau- food Dapli- nau- 



nia plii ' nia plii ' 



n\a 



plii' 



Dry 

 food 



u. 



0.05 

 .05 

 .05 

 .05 

 .05 

 .05 

 .05 

 .35 



1.0 

 1.0 



1.0 

 1,0 

 1.0 



0.4 

 .■1 

 .4 

 .4 

 .4 

 .4 



2.4 



a. 



0.10 

 . 10 



. 10 



, 10 



.10 

 .10 

 , 10 

 .70 



l.-s 



1.5 

 1.5 

 1.5 

 1.5 



0. fi 

 .0 

 .6 

 .0 

 .6 



a. 



0.15 

 .15 

 .15 

 .15 

 .15 

 .15 

 .15 



1.05 



This represents wciglit of eggs hatched, .\cuial weight of nauplii pro- 

 duced, for the "stimdard" diet was 0.125 mu. (Sillinian and Outsell. 195S). 

 The determination was made hy producini; duplicate hatches of (i.4 p of 

 eggs; the«e hatches were then dried, weigiied. and the average weight deter- 

 mined. No data were available to adjust for dav-I(i-<iav variations in liatching 

 success. Tlie weiglit of nauplii renre'ented such a small p-rt of the total diet 

 (about lioo of 1 percent) that variations would not signiflcantlv affect total 

 food available. 



The nine populations were started on Janu- 

 ary 30, 1964. (A list of dates for the numbered 

 weeks of each e.\i)eriment is given in table 2.) 

 Stocks were from jjreviously established aquari- 

 ums and consisted of 432 guppies. T segregated 

 the fish into males, females, and "juveniles," the 

 latter including the categories "fry" and "imma- 

 ture" as defined above. All males were placed in 

 a single container and then |)ut into the nine 

 tanks from .\ t o I in succession, one fish at a time. 

 1 rejieated this jirocess until seven males were in 

 each tank. I used a like process to put eight 

 fcniiiles in each tank. Siniihu-ly, 33 juveniles weic 

 placed ill each tank, but they were introduced 

 in groups of 10, 10, 10, and 3. Thus, each tank 



contained 4S fish — 7 males, 8 females, and 33 

 juveniles — chosen in a consistent manner from 

 established aquarium stocks. 



Populations were fished (exploited) at 3-week 

 intervals, the approximate time between broods.' 

 These rates bracketed the rate previously found 

 to produce maximum yield (Sillinian and Outsell, 

 195S), which wiis about 0.33 per 3-week period. 

 'I'he "bracketing" rates were 0.25 and 0.50 jior 

 3-week i)eriod. Fishing was done by remo\ing 

 each nth fish for fishing rate ,7 and was applied 

 only to the "innuature" and "adult" fish, exclud- 

 ing the "fry." "Adults" included all fish whose 

 sex (diild bo determined by external ins])ection: 

 and "imniatures", all others excejit the "fry" 

 that passed through the grader described above. 



I'roccdures were described in moi'O detail hy 

 Sillinian and Outsell (1958), who also reported 

 the technique of weekly counting and weighing 

 the fish. This essentially consisted of counting 

 fish individually and j)lacing them on a strainer. 

 From the strainer fish were transferred to a \n-e- 

 \iously weighed container of water on a hahince. 



Table 2. — List of calendar weeks included in experiment 



Weelc No. 



Beginning 



Year, month, 

 and day 



Week No. 



Beginning 



Year, month, 

 and day 



;96.jJan. 26 37 ;SS< Oct. 



3- 



4. 

 5. 

 6. 



s! 



9 



10. 

 11. 

 12. 



13. 



14., 

 15. 

 16., 

 17- 

 18- 

 19., 

 20- 

 21-, 



23. 

 24. 

 25- 

 26. 

 27. 

 28- 

 29. 

 30. 

 31. 

 32. 

 33- 

 34- 

 35. 

 36. 



2 

 9 

 16 

 23 

 1 

 8 

 15 



■]« 

 5 

 12 

 19 

 26 

 3 

 10 

 17 

 24 

 31 



14 



21 

 28 

 5 

 12 

 19 

 26 



9 

 16 

 23 

 30 



Sept. 6 

 13 

 20 

 27 



Oct. 4 



Feb. 



Mar. 



.\pr. 



May 



July 



Aug. 



38. 

 39. 

 40. 

 41. 

 42- 

 43. 

 44. 

 45. 

 46. 

 47. 

 48. 



Nov. 



Dec. 



49. 



50. 



51- 



52- 



53. 



54. 



65. 



56. 



57. 



.58. 



59. 



60 



61. 



62. 



63., 



64- 



65. 



66. 



67. 



68. 



69 



70. 



71. 



72., 



I9S5 Jan. 



Apr. 



May 



11 



IS 



25 



1 



8 



15 



22 



•29 



6 



13 



20 



27 



3 

 10 

 17 

 24 

 31 



14 

 21 



14 

 21 

 28 

 4 

 II 

 18 

 25 



9 

 Hi 

 23 

 30 



6 

 13 



I Each brood consists of 6 to 60 young, depending on the size of the female 

 (Innes. 1945). 



428 



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