24 



Conservation Department 



hi the case of Green lake, oxygen was absent from the 65 foot 

 level down to the bottom (185 feet). At a depth of 45 feet, oxygen 

 was present to the extent of 8.8 p. p.m., and with a temperature of 

 11 °C, suitability for a limited number of trout was established 

 over a rather large area and depth. 



Table 7. — Temperature and Gaseous Relations in Green Lake, 

 August 27, 1927 



DEPTH IN FEET 



Temp. C° 



O2 p. p.m. 



*C02 p.p. m. 



pH 



Methyl orange 

 alkalinity 

 as p. p. m. 

 calc. carb. 



Surface 



25 



20.3 



15.7 



11. 



10.5 

 9.4 

 9.8 



6.9 

 11.9 



8.8 

 0.0 

 0.0 

 0.0 



0. 



8 

 10 

 55 

 65 

 80 



8.1 

 7.6 

 7.5 

 7.1 

 7.1 

 7.1 



132 

 183 



45 



65 



185 

 305 



95 



327 



185 



388 







* Ibid., page 23. 



Other Factors Studied.— Among the other factors to which 

 attention was given for the purpose of determining the particular 

 species to be planted, were size of stream, velocity, character of 

 bottom and barriers to fish movements. Since these were dis- 

 cussed in the Genesee report, it is sufficient here to say that the 

 size of the water course often determines the practicability of 

 assigning bass; the velocity and character of bottom indicates 

 whether it shall be the large or small-mouthed bass with such 

 associated species as yellow perch, bluegill sunfish and catfish, and 

 finally with reference to barriers, their presence may eliminate the 

 rainbow trout from consideration in many a stream otherwise 

 suitable. 



Factors Influencing the Number of Trout to be Planted. — 



The more important of these are area of stream available to trout, 

 abundance of primary food organisms, pool conditions, and the 

 effects of angling. 



Area: The available foraging area was calculated from the 

 average width and the total length of stream bed over which trout 

 might range, the latter being greater than one might at first sup- 

 pose. During the colder months from September to June water 

 temperatures are low enough to permit trout to forage almost any- 

 where barring other unsuitable conditions, But during the hot- 

 test parts of the year in June, July and August the foraging area 

 may be greatly curtailed by temperatures above the endurable 

 points. It becomes necessary to assign a somewhat greater area 

 than that based solely upon the summer ranges of trout. 



Primary Food Organisms: Quantitative estimates were made in 

 essentially the same manner as reported for the Genesee Survey 



