American Fi,'<]ieries Society 241 



I have thus hastih' and imi^erfectl}' sketched the respira- 

 tion of an inland lake, not because the story is known with any 

 fullness or completeness, but partly because our present knowl- 

 edge, imperfect though it is, shows that the subject is one of 

 great scientific interest; partly also because many practical 

 hints regarding the utilization of lakes in fish culture can come 

 from our knowledge of respiratory conditions. We are accus- 

 tomed to think of the food producing capacity of the lake as the 

 factor which determines the kind and amount of the crop of fish 

 which it can produce. It is a somewhat new thought to me, and 

 I have no doubt that it is equally new to many of you that the 

 respiratory capacity of the lake may have even greater influence 

 in this matter than has the capacity for the production of food. 

 Yet it is plain that such is the case and that a knowledge of the 

 respiratory conditions of the lakes in which our fish are to be 

 planted is necessary if the best results are to be reached. 



DISCUSSIOX. 



^Ir. Titcomli : I just want to say one thing in connection with 

 the question of "Eospiration,''' and that is the use of the outlet of 

 a lake as a water sup])ly for fisli culture i)urpos('s. Dr. Bean in 

 his enumeration of a few of the troul)les, mentioned the fact that 

 it was difficult even in the state of Xew York to find suitable 

 water su])])ly. Xow. I have always entertained the thcorv that to 

 get an al)uudant sujiply of water for an immense trout hatcliery, 

 perhaps larger than any in existence, the outlet of a lake would 

 l)e the ])roper source. Dr. Birge brings out again, as he did 

 last year, some of the difficulties to be encountered. At the 

 same time. I think that his investigations, or investigations 

 along the same line, would definitely determine whether it is 

 safe to use the outlet of a lake. In other words, in the summer 

 time, we wish to gut an abun.dance of cold water. Xow. the 

 question is, whether we can go to a lake and draw the water from 

 a certain depth to get cold water, and at the same time get water 

 containing the proper amount of oxygen. I infer from his 

 ])a])er, that it can lie easily determined at what de})th we can 

 th'|)end u])()n a certain temperature of water and at the same time 

 determine whether the water at that depth contains sufficient 



