American Fislt cries Society 243 



you would haA'c to consider carefull}^ whetlier the lake would 

 stand that drain upon it, because by far the greatest source of 

 water is at the surface and immediately below the surface. 



If you will o-o to a lake in August or September, and de- 

 termine the question of temperature and gas, which is a very 

 easy thing to do, that w^ill tell the story. 



President: Is there anything further in this matter? 



Mr. Se3'mour Bower: It is a very important paper and has 

 a great deal of practical value. I think the planting of a great 

 numy of the fish which we are now planting might be avoided. 

 We plant a good deal of lake trout l)y eggs. 



President: I believe that if you are going into planting 

 lake trout or whitefish in any inland lakes, it would pay you to 

 have the lakes examined before you put the fish in; but I hope 

 to be able to say that positively next year. Last year we did 

 this, which shows you something about it. You know the black 

 fin, which is the common whitefish of our inland lakes (nigripen- 

 n is ) , it has been said goes to the bottom in summer. Now unless 

 it goes into the mud like a frog in the winter, it cannot gO' down, 

 because these lakes have no oxygen in the l)ottom water 

 We were working on one of the lakes in northern Wisconsin, 

 a lake alK)ut fifty feet deep, and we happened to set our gill 

 net right across this point in the lake where the cool water be- 

 gins. The inner end was in the warm w^ater, and the outer in the 

 cool water, and when the net was taken wp, there were perhaps 

 eight or ten of these black fins, and they came from the lake just 

 at this junction. Now it seemed to us that this showed, as well 

 as one experiment could show, the fact that this fish was living" 

 in water whicli was just as cold as it could find oxygen in. So 

 that tliere Avould Ije only a pretty limited area in that lake in 

 Avhich that fish could live. 



Mr. Clark: On account of the temperature of the water — 

 did that have something to do with it ? 



President : They would not come up in the warm Avater any 

 more than was necessary. They probably liked the cold water. 

 But they would go down into the cold water as far as they could. 



