PAPERS PRESENTED AT GENERAL SESSIONS 89 



been true, a study of the biological situation led to the 

 belief that no one of them had the slightest relation to 

 the sudden disappearance of this important food supply 

 formerly secured from Devils Lake. TThat really had 

 happened was that due to the isolation of the Devils Lake 

 waters from fresh water lakes to the north ha^dng a 

 slightly higher altitude, with the increased dessication 

 during the arid years from 1SS5 to 1890. the water level in 

 the fresh water lakes and in Devils Lake had fallen be- 

 low the bottom of the creek or coulee channel which con- 

 nected them. The great northern pike apparently fol- 

 lowed the habits of the ocean salmon and migrated in 

 early spring, passing through the connecting coulee to the 

 sweet water lakes north, where shallow fresh water beds 

 produced large areas of favorable spawning gTound. thus 

 insuring the propagation and continuance of the swarm- 

 ing pike. In the autumn, it was reported that the pike 

 migrated from the shallow sweet water lakes to the 

 deeper, and therefore better i^rotected winter habitaf of 

 De^'ils Lake. When the connecting coulee dried up and 

 Devils Lake became segregated from the spa^\Tiing 

 grounds in the sweet water lakes, reproduction of pike 

 ceased. Obviously, if an organism is prevented from 

 propagating itself, it soon vanishes from the earth, as 

 did the wild pigeon. 



Following the studies of the physiographic, physical, 

 and chemical changes, certain experiments were initiated 

 in the adaptation of higher plants and animals to the 

 water of Devils Lake. These organisms were taken from 

 bodies of sweet water T^'ithin the neighborhood of Devils 

 Lake, or secured from the L'nited States Fish Hatchery. 

 Experiments were tried with yellow perch, rainbow 

 trout, bull heads, and other material available for ex- 

 perimentation. Perhaps the following details of a few 

 experiments may be sufficient for this report of the physi- 

 cal reaction of higher organisms in the water of the dving 

 lake: 



Prior to the initiation of our studies at the Biological 

 Station in 1909, many attempts had been made to restock 

 Devils Lake Avith fish. Much private, municipal, and fed- 

 eral money had been spent in fruitless etforts to secure 



