BULLETIN OF THE UNITED STATES FISH COMMISSION. 269 



0> THE FOOB OF YOUIVC; AVHITEFSSII (COREGONITS). 

 By S. A. FORBES. 



[Letter to Prof. S. F. Baird.] 



Please allow me to add to the facts relating to tlie first food of the 

 whitefish, detailed in my letter of last spring, the following notes from 

 recent observations : 



According to an arrangement made with Mr. Frank X, Clarke, I went 

 toKacine, Wis., on the IGth instant, in order to search the lake for minute 

 animal life at the place where it was i)roposed to plant a lot of young 

 whitetish. Mr. Clarke's party made better railroad connections than 

 he expected when he telegraphed me, and the fish had been released 

 about nine hours when I arrived; I took a boat as soon as possible, and 

 made a careful search for entomostrapa in the water of Eacine Eiver, 

 near its mouth, and in the lake at various depths and distances from the 

 shore. 



The entomostraca occurring were all of species which I had previously 

 collected off Chicago and in Grand Traverse Bay, viz, an undescribed 

 Cyclops [C. T/<o»ms/, MSS.), an undescribed variety of I>iaptomus gra- 

 c?7»sSars; a new species of centropages (especially interesting, since the 

 genus has been hitherto unknown only from saltwater); and Daphne 

 (jaleata f Sars. 



The Cyclops and diaptomus were about equally abundant, but the 

 centropages and daphnia were much less common. All were much more 

 abundant in the rivers than in the lake, and in the latter were more 

 numerous at or near the bottom than at the surface. This was perhaps 

 owing to the cool and lowering weather. Immense numbers of diatoms 

 lined the towing net after every haul, with a brownish, mucilaginous 

 coating, the vegetable life far surpassing the animal in quantity. 



I dragged the towing net as nearly as possible a quarter of a mile at 

 each haul, and saved each time the entire contents of the net. Taking 

 a definite part of the product of the most fruitful haul and counting the 

 entomostraca in this, I reached the conclusion that they occurred here 

 at the rate of two or three to the cubic foot of water, or, taking favor- 

 able and unfavorable situations together, at about one or two to tlie 

 foot; this suggests the j)ropriety of scattering the deposit of fish as much 

 as possible, unless it is certain that they scatter rapidly when left to 

 themselves. It should be noted that the most abundant species here 

 at this season of the year were, fortunately, the smallest. IMr. Clarke 

 kindly gave me a few young fishes left in one of the cans, and I suc- 

 ceeded in getting about twenty-five of them home alive. 



I put these in a small aquarium with well-water on the 17th and sup- 

 plied them with entomostraca and alg® of various kinds from the pools 



