.■iincricaii Fisheries Soeiety. 75 



'I'lic ones ill tlu' ri\crs ahoxc ilic dams arc longer, slimmer 

 and more fusiform : those in the lake, wliieli never enter the 

 rivers, are shorter, broader, and more ctMiipresscd. 



There is also an intermediate between the two, partaking of 

 the eiiaraeteristics of b(nh. These come from the lake into the 

 mouths of the rivers and up to the lirst dam to feed and to s])awii 

 in the spring and to feed in the fall, and it is not imirrobable that 

 they also hibernate there, as 1 have caught them there late in 

 the fall on a warm day, after hard free?:ing weather had set in. 



The pike-perch of Sandusky Hay is easily distinguished from 

 its s])ecies taken about the islands in the main lake, I)eing more 

 fusiform and longer for a given weight besides being of a decifled 

 yellow cast, while the lake fish is broader, more compressed and 

 the yellow shades almost or (piite wanting. It may be interesting 

 to state, in passing, that the ]Mke-])erch taken in the Lake of the 

 Woods in Canada — many of which are brought to Sandusky to 

 be marketed — cannot be told from those taken in Sandusky I>ay 

 by the commercial fishermen wiio are liandling them constantlv. 



These dififerences are persistent to a well nigh universal de- 

 gree, and perhaps might be worked out in the more minute struc- 

 tural lines as to fin ra^•s, scales, etc. 



Prof. Birge: Yes, they could be; the cpiestion would at once 

 arise whether these differences are sufficiently permanent. For 

 instance, you brought stream black bass into a lake, will they keep 

 the stream form or assume the lake form? 



iMr. Stranahan : You may stock a stream ever so well with 

 black bass from Lake Erie and if they can possibly get back to 

 the lake, they will get there. We know that by experience; the 

 ones planted from Sandusky Bay. planted in Chagrin river didn't 

 show up at all. I should expect to see tiiat hereditary disposition 

 show up for one or tw'o generations. 



Prof. Birge: How is it about stocking lakes with stream 

 fish? 



Mr. Stranahan: They would go to the streams if they could 

 get there ; their hereditary disposition doubtless would carry them 

 into the streams. 



Prof. Birge: The professor has used for practical purposes, 

 one of the newer methods in biology. One thing that biologists 

 have been doing recently has been to get at the average of 

 structure and to state the amount of variation from the average. 

 They have l)egun to measure in a large number of individuals 



