472 



PLANKTON PRODUCTION AND TEMPERATURE. 



u 



January 



February 



March 



April 



May 



June 



V 



d 

 E 



<u 



H 





d 

 6 



H 



OJ O 



d 

 E 



c c 



as O 



Oh *" 



d 

 E 



<L> 



H 



a a 



as 



d 

 E 



H 



C C 

 cd O 



d 

 S 



H 



a a 

 as 



Ph ~ 



1894 

 1895 



1896 



1897 



1898 

 1899 





















80.25 



80. 



74-7 



75- 



78.8 



O.74 

 30.42 

 O.72 

 O.27 

 396 







32. 



33-7 



32.25 



32.12 



32.6 



O.OI 

 0.02 

 O.O4 

 O.27 

 0.8l 







58- 

 64.54 

 60. 

 53-32 



3-i8 

 5.67 

 5. 11 



4.40 







32.75 



O.OI 



39-52 

 43-8 

 43-3 

 35-2 



0.07 

 O.38 



0-33 

 O.28 



72.7 

 66.3 

 65.8 



I .30 



5.62 



II.30 



32.7 

 32-9 



0.45 

 0.18 











u 



July 



August 



September 



October 



November 



December 





d 



ri 



d 



j* 



d 



Jt 



d 



^i 



d 



J<S 



d 



M 







c s 



S 



c a 



OS O 



S 



as O 



E 



c a 



as O 



E 



a c 



os O 



E 



nj O 





H 



Ph 



H 



Ph 



H 



Ph 



H 



Ph 



H 



Ph 



H 



Ph 



1894 



82.25 



5.12 



83-5 



9.67 



77-5 



I.36 



58. 



0.6l 



41. 



O.IO 



39- 



0. 10 



189s 



79- 



9-33 



80.51 



4-03 



78.87 



1.52 



54.26 



O.57 



42.5 



3.02 



37-5 



I. 14 



1896 



80.7 



1.44 



82. 



I . 12 



65-75 



O.38 



56. 



I . II 



44- 



0.02 



33-6 



O.76 



1897 



81.02 



4.69 



80.9 



3-65 



77.07 



8.83 



65.1 



5-95 



45-7 



1. 00 



33-02 



O.56 



1898 



82.87 



0.58 



80.56 



O.QI 



71.87 



O.69 



54-37 



0.24 



41.42 



O.25 



32.98 



O.99 



1899 













































in Thompson's Lake, 29 per cent. The difference would be in- 

 creased if the aberrant data of the late autumn of 1897 were 

 removed from the records. Low temperatures thus tend to 

 depress production in both channel and backwaters, and high 

 temperatures to increase it. 



The minimum production of the year occurs in the river, 

 and with few exceptions in the backwaters, in January-Febru- 

 ary, the two months of minimum temperature. With the 

 period of rising temperatures in March-May there comes gen- 

 erally at all of the stations a rapid rise in plankton production, 

 culminating in the vernal pulse in the last days of April or the 

 first of May at about 60°-70°. The effect of this is seen in the 

 generally high average production in April and May in both 

 channel and backwaters. With the establishment of the sum- 

 mer period of maximum temperatures, which includes the 

 months of June-September with the exception of a few days 



