130 Fortieth Annual Meeting 



The fish began to clean their nests in the other four lakes 

 about May 20th, the water temperature at the time being 

 56°. Altogether, by the 1st of June there were nearly four 

 hundred nests either with eggs or ready for them. Indeed 

 the fish were hatched in perhaps fifty nests. 



From May 20th until June 1st the weather while not cold 

 was mostly rainy and cloudy and the water temperature 

 varied between 56° and 58°. There was a sudden change 

 in the weather June 2d. That night there came a cold snap 

 with frost sufficiently sharp to kill young leaves of trees. 

 While there was frost only one night the weather continued 

 very cold until June 12th when it gradually moderated, but 

 did not become warm until the 16th. By June 5th the water 

 temperature in the four lakes had fallen to 48° and it re- 

 mained about that point until the 12th of June. The lowest 

 point recorded was 46°. Between June 12th and 16th the 

 water temperature rose gradually to 58°. 



Simultaneously with the fall in the water temperature 

 every nest that did not contain eggs was promptly abandoned 

 by the parent fish. An examination on the morning of June 

 4th of the nests showed that the unhatched eggs had assumed 

 a dullish color. By the following morning fungus had 

 developed, and within two or three days every tgg had dis- 

 appeared, probably devoured by small fish. The parent fish 

 abandoned the nests containing eggs as soon as fungus 

 developed. A constant inspection of the nests containing 

 fry showed that the young fish clung closely to the bottom 

 without any sign of motion, and for the next week there 

 was very little absorption of the sac visible, and at the end 

 of ten days the sac was hardly more than half absorbed. 



While there was no apparent activity among the fry in 

 many instances they actually did move and at the end of ten 

 days the fish in nearly half the nests had scattered over a 

 radius of ten feet or more. In this connection there was one 

 very curious incident. On one lake under my own charge 

 there were three nests about six or eight feet apart and on 

 a sloping bottom. All the fish from one of the lower nests 



