Biological Survey — Oswego Watershed 183 



influence on the inland fisheries is considerable. On the good, 

 or credit side their young, the ammocoetes or mud-lampreys, are 

 excellent bait for fishing, and no doubt many of them serve as 

 fish food when washed from the mud-banks by freshets, also when 

 migrating down the streams to the lakes. 



When they reach the lakes, there is, so far as known, no good 

 economic side. They prey upon the food fishes, and in return 

 never are turned into human food as are the sea lampreys. The 

 food fishes that I have known to be attacked are: pike, pickerel, 

 bullheads, carp and suckers. Although present in Lakes Erie and 

 Ontario, their destructive habits have been most studied in con- 

 nection with the fishes of Cayuga, Seneca and Oneida lakes. They 

 attack all food fishes, and when hungry enough, attacked a ganoid 

 (bowfin) in our aquarium. According to Surface* and Bensley, 

 they have been known to tackle even a gar pike. (Lepisosteu-s 

 O'sseus). Old fishermen have told me that when the sturgeon 

 was still found in Cayuga lake, the lampreys were particularly 

 attentive. Often six or seven might be found attached to one 

 fish, something as shown for the carp in Figure 1. 



Drs. Smallwood and Struthers, investigating the carp in Oneida 

 lake this summer (1927), told me that often more than half of 

 the carp in a haul would be lamprey marked. Dr. Eaton in 

 his work found that 34 out of 38 of the lake trout caught in 

 Seneca lake were lamprey marked; and in Cayuga lake, two of 

 the four trout caught were so marked. Several years ago 

 when there was commercial seining of carp in Cayuga lake the 

 fishermen told me that fully half of the carp seined had lamprey 

 marks upon them. Dr. Embody in securing fish early in the season 

 for the spawn for the Cornell fish hatchery, told me that he had 

 never found more fish that had been mangled by the lampreys. 

 The large number of mature lampreys at the head of Cayuga lake 

 this spring was abundantly confirmed by me later in collecting 

 them on the spawning grounds. They seemed as numerous as 

 twenty-five years ago. 



As pointed out to me several years ago by Dr. A. H. Wright, 

 the depredations of lampreys are greater at the head, or southern 

 end of Cayuga lake than near the foot, and Dr. Eaton told me 

 that this summer more of the fish at the southern or upper end of 

 Seneca lake were lamprey marked than at the lower or northern 

 end. The observations of Drs, Smallwood and Struthers in 

 Oneida lake this season, point in the same general direction, that 

 is, in all the lakes, the greatest destruction by lampreys is near the 

 entrance of the streams in which they spawn. In Oneida lake 

 the spawning streams are more distributed than in Seneca and 



* Surface, H. A. The Lamprevs of Central New York. Bulletin of the 

 U. S. Fish Commission, Vol. 17, 1897. 



