American Fisheries Society 101 



DISCUSSION. 



Mr. Frank N. Clark : I question a 15 per cent, increase on wliitdlsh, 

 as I do not think the tests of one year sufficient for definite conclusions. 

 I would like to see the investigations carried on for several years. i\Ir. 

 Downing's experiments, no doubt, covered just the one season of 1906. 

 While we never have made exactly similar tests, I think in measuring 

 with the von Bayer gauge we found about the same number at all 

 times of the season. Notwithstanding Mr. Downing's experiments for 

 one year, I doubt whether it can be established that from the time white- 

 fish eggs are thoroughly water hardened, say when four or five days old, 

 there is this increase in size when they are two or three months old. 

 However with lake trovit eggs it nuist be confessed lliat our measure- 

 ments for several years have shown quite an increase. 



Mr. S. W. Downing: If I remember correctly, I made two experi- 

 ments. The first was by actual count and the second by means of the 

 von Bayer gauge. The results are as stated Iw Mr. Bower. 



Mr. Clark : Both the same season ? 



Mr. Downing: Not the same season. The count was made before 1 

 knew of the von Bayer measure. I would like to say in summing up 

 Mr. Bower's paper that it looks a little misleading as regards tlie number 

 of fry we actually put out. The eggs are measured into the hatchery 

 on the higher standard, 42,000 to the quart, but as the}' increase during 

 incubation the hatching is done on a 36,000 basis. So we plant just as 

 many fry as we say we do. 



Mr. S. F. Fullerton : I find that the difference, especially in pike 

 perch eggs, is very noticeable. We have one station where by actual 

 measurement they did not exceed 120,000 to the quart, but at Tower 

 where the fish are all small, not averaging more than a pound and a half, 

 our men counted as many as 185,000 per quart. There was a difference 

 of 65,000 by actual count. 



Mr. Clark : Of course that is not exactly the question here. Those 

 eggs were from different waters and taken at different times. The same 

 difference occurs with whitefish, for if I remember correctly it is very 

 noticeable in whitefish eggs taken in upper Lake Michigan. These run 

 only about 30,000 to the quart, l)eing much larger than those from Lake 

 Erie. 



Mr. Fullerton : The reason I l)rought the suiiject up is that I just 

 asked Mr. Titcomb in regard to the Federal standard for measuring pike 

 perch eggs. It is difficult to (^^ a definite standard if the other states 

 have had the same experience that Minnesota has. 



Mr. John W. Titcomh : At an earlier meeting of the Society I 

 endeavored to point out the value of the von Bayer measure. You 

 cannot make a standard for any of the smaller eggs nor in fact for the 

 larger eggs. It has been my experience that with almost all species 

 there is a variation in the size of eggs between one field and another, 



