American Fisheries Society 87 



and the freezing over of the pond, however, there was a sud- 

 den change. One day the Superintendent noticed two or 

 three dead sturgeon under the ice and on making an examina- 

 tion he saw a numbef of others which, though still alive, 

 were e\-idently in the last throes against the ice in the shoal 

 water. Calling his men he cleared the ice from the pond, 

 drew the seine, and caught all the sturgeon, to find every one 

 either dead or dying. 



No satisfactory explanation of this fatality has been 

 evolved. I give the few theories advanced for what thev 

 may be worth. One was that they had been driven from the 

 deeper portions, by the more than 700 mature catfish, into 

 the shallower and much colder water of the pond, and that 

 the temperature was too low for their existence. A second 

 was that the entire temperature of the water was too low, 

 there being a difference of about two degrees between the 

 water in the catfish pond and the bottom water of the perch 

 pond. A third was that there was not enough change of 

 water during the low temperature period. Some color was 

 given to the cold water theories by the fact that all the fish 

 still alive when taken from the pond were stiff and with the 

 same appearance as trout kept for any length of time in tanks 

 during very cold weather without vigorous aeration of the 

 water. 



When the nets were operated in the river in the spring of 

 1909 more sturgeon were procured, also of the short-nosed 

 species. This time Mr. Berkhous selected the sexes in the 

 proportion of one-third females and two-thirds males. They 

 were placed in two small ponds where they could be handled 

 easily and gone over each day. On April 9 he found the first 

 ripe female. A few days before he had found several nearly 

 ripe males. 



As the female was taken from the water eggs flowed from 

 her without any pressure for a moment and then stopped. 

 On replacing the fish in the water and again removing her. 

 the eggs once more flowed. This fish, which was a little over 

 two feet long, was stripped with the greatest ease, at least of 



