BREEDING BEHAVIOR OF SUCKERS AND MINNOWS. 3 



The drawings that show fish in action have been made from 

 field notes and sketches with the help of specimens and in some 

 cases with the aid of models or photographs. I am indebted 

 to Mr. Charles R. Knight for valuable suggestions in connection 

 with the drawings but he is in no way responsible for their 

 obvious shortcomings. To my former student, Professor 

 Norman H. Stewart, of Bucknell University, I am indebted for 

 data from his unpublished manuscript on the distribution of the 

 pearl organs. To the United States Commissioner of Fisheries, 

 Doctor Hugh M. Smith, I am indebted for permission to publish. 



2. BREEDING BEHAVIOR OF THE SUCKERS. 

 A. The While Sucker (Catostomus commersonii LeSueur). 



i. The Breeding Grounds and Breeding Season. A little way 

 from the State Bass Hatchery, near Grand Rapids, Michigan, 

 Mill Creek is spanned by a bridge of the Pere Marquette Railway. 

 Just below the bridge, where the stream is three or four rods 

 wide, a line of four-inch waterpipe is laid across its bed. An 

 eighth of a mile above the bridge the stream is dammed to furnish 

 water for the hatchery. Between the dam and the pipe-line it 

 is made up of a series of alternating rapids and pools. For a little 

 distance above the bridge and beneath it the water runs six to 

 twelve inches deep, swift and smooth. Below the pipe-line it 

 breaks into ripples. Under the smoother water the bottom is 

 sandy gravel, but under the broken water this gives place to 

 larger stones. Over the gravel in the smoother water a thin 

 brown mantle of silt and algal growth usually stretches without 

 interruption from shore to shore and obscures the bottom. 



Rapids of this sort are typical of a drift-covered country and 

 afford the characteristic breeding ground of the white sucker. 1 

 In the spring patches of the gravel bottom in the upper water 

 of the rapids often look as though they had been scoured by a 

 broom. The silt mantle is absent from these patches and the 

 bright colors of the clean gravel and sand throw them into 



1 The usual name in Southern Michigan; known also as common sucker, fine- 

 scaled sucker, brook sucker. 



I am indebted to Professor W. M. Smallwood for permission to use his un- 

 published notes on this species. He records seeing it in the spawning attitude on 

 stony bottom in Lake Clear in the Adirondacks in late June (cf. Reighard, 1915)- 



