580 REPORT OF THE COMMISSIONER OF FISHERIES. 



lake. This was the so-called silvery lamprey, Ichthyomyzon eoncolor.'* 

 1 inquired of the fishermen if they had ever seen the lamper eels 

 attached to fish, and they said, " yes;" to the inquiry as to the kind of 

 fish the reply was, "carp." On the 10th of August, 1902, I was 

 assisting in making a seine haul of carp in the Sandusky River when 

 one of the fishermen noticed a lamper " about 5 inches long " attached 

 to one of the fish; it became detached, however, and escaped through 

 the net before I could get to the place to see it for myself. Prof. S. H. 

 Gage tells me that in his aquaria at Cornell University the young of 

 the Cayuga Lake lamprey {Petromyzon tnarinus unicolor) have become 

 attached to carp as soon as they were transformed from the larval stage 

 and had left the sand. As carp are abundant in Cayuga Lake, as well 

 as most of the other lakes in which this lamprey occurs, it seems very 

 probable that during its free-swimming life the latter may be one of 

 the important enemies of the carp, as it has been found to be of many 

 other fish (Surface, 1898). In fact. Surface (p. 212) includes carp 

 among those fish he has found dead with the marks of the lampre}^ on 

 them. 



Finally, under unfavorable conditions carp, like other fish, are sus- 

 ceptible to the attacks of fungus growths. So long as the water is 

 pure there seems to be little danger of this, for I have seen carp that 

 had been penned for long times whose heads were much bruised and 

 abraded, but which were free from fungus. On the other hand, some 

 young fish which I attempted to keep in an aquarium at Ann Arbor 

 were soon attacked by a Saprolegnia^ and I was unable to keep 

 them alive for more than a few weeks on that account. The usual 

 treatment with potassium permanganate and by immersing the fish 

 for a short time in strong brine afforded only temporary relief. 

 Smiley (1886, p. 754) gives the following with regard to carp attacked 

 by fungus: 



Statement of B. E. B. Kennedy, Omaha, Douglas County, Nebr., April 14, 1883. 



Fungus. — On visiting our fisheries yesterday I find that many of the young carp 

 are affected with a kind of parasite or fungus, which proves fatal. With some it 

 appears on the back, some will have a strip nearly around the body, and some about 

 the fins and tail. This fungus is easily removed, and the skin or flesh under it has 

 the appearance as if the spot had been blistered. Several hundred have already 

 died, and many more are similarly situated, and, unless there is some remedy 

 administered, all will be likely to die. We have separated the affected ones from 

 the others, hoping to stay the spread of the disease, if it is one. Those that show no 

 fungus appear all right and take food readily. 



Note by Professor Baird on fungus. — When the carp are taken from their 

 winter quarters for our spring shipments there seems to be a general tendency to the 

 development of the fungus. It is probably due to the abrasions produced in handling, 



o In color these specimens agreed more closely with the description of Ichthyomyzon castaneus 

 Girard. 



