On liay 2, a rainbow trout, 26.0 inches in total length, was con- 

 fiscated from a sucker spearer ivho had taken it in the estuary of 

 the creek „ This fish had a fresh laraprey injury 2 l/U inches in 

 diameter and nearly l/k inch deep. A 2U. 5-inch female rainboiv 

 trout which cane dovmstream on Ilay 12 bore two recent lamprey scars 

 and one which was nearly healed,, A third rainbow trout,, 17«9 

 inches longj talcen in the trap on May 26 had an old, healed-over 

 scar. One northern pike, 19.6 inches long, taken on ICaj 1 had two 

 fresh lamprey wounds. No bullheads or rock bass had lamprey marks. 



Carp Creek , 19h3: — Of 2j8I;S white and redhorse suckers trans- 

 ferred upstream, 6,8 percent bore one or more relatively fresh or 

 recent lamprey scars. The degree of scarring of these species was 

 hardly different from that e:d.sting in 19U7 although the size of 

 the run had declined appreciablj''. No other species had any evidence 

 of lamprey attacks in this year. 



Carp Creek , lSk9t — Of 1,311 white and redhorse suckers taken 

 in the trap, 311 or 17.2 percent bore one or more relatively fresh 

 or recent lamprey scars. In this year, the degree of scarring in- 

 creased very markedly and the size of the sucker runs continued 

 to decline at a rapid rate. No other species gave evidence of 

 lamprey attacks. 



Ocqueoc River , 19U9 s —A total of 3,137 white and redhorse 

 suckers was taken moving upstream. Of these, 801 or 25.5 percent 

 bore relatively fresh or recent lamprey scars, exceeding the Carn 

 Creek data by 8,3 percent. Of lOU rainbow trout transferred up- 

 stream, 23 or 22.1 percent had been scarred by lampreys- No indi- 

 viduals of any other species taken carried marks. 



(U) Occurrence of lamprey-s carred sea lampreys 



In 19U8, the first evidence of what might be termed cannibalism 

 was observed i Tiventy-four sea lampreys were taken in the Carp Creek 

 weir which bore lamprey scars. Appro:dmately the same incidence of 

 similarly injured sea lampreys was observed in 19U9 although no exact 

 records were kept in that year. Some of these scars upon the lam- 

 preys were quite superficial and may, perhaps, be attributable to 

 some premature manifestation of the spavminr urge. Kost« however, 

 Trere deeper scars ■which penetrated the musculature. The implications 

 of these scarred lampreys are somewhat obscure since we know so little 

 of the feeding habits of the species. They may, in some degree,, 

 indicate an increasing shortage of the species which comprise their 

 usual victims or they may be entirely fortuitous in nature,, 



Relative abundance of sea lampreys 



One function which the weir-traps operated during these studies 

 may serve is to provide information on annual fluctuations in abundance 



- 51 - 



