The question has been raised often as to whether or not sea 

 lampreys feed during raigr-ationo I have e-'ri.dence that they feed 

 rery little if at all. This evidence was obtained by analysing 

 the contents of lamprey digestive tracts and by examining other 

 fash present in the same waters, durinr: a migration, for lamprey 

 scars. The dissection of migrants taken from both Carp Creeic and 

 the Ocqueoc River presents very strong evidence that feeding ceases 

 with approaching sexual maturity and with upstream movements Of 

 2,2U9 migrating sea lampreys opened in iSW^ fron Car-p Creole and the 

 Ocqueoc River :, only one specimen showed any evidence of recent 

 feeding. 



Between May 29 and July 15 ^ 19U73 netting operations inere 

 undertaken in Ocqueoc Lake utilizing 125-foot experimental gill 

 netsc Twenty-eigjit sets were made averaging 2k hours each. During 

 the period of netting operations, migrant sea lampreys were con- 

 centrated in greater or lesser numbers in the lal<:e while in passage 

 to the upper reaches of the watershed. A total of 69 adult sea 

 lampreys and 11)| game, pan, and coarse fishes of assorted average 

 length Tvere taken as follows; 2? northern pike, 21,7 inches; Ul 

 rock bass., 6o3 inches; 2 black bullheads, 9»5 inches; u blue gills, 

 UeO inches; 28 yellovir perch^ 5o7 inches; 2 largemouth bass llo9 

 inches; 6 white suckers, 13»3 inches; 2 walleye pilce, 11»5 inches; 

 and 2 pumpkinseed sunfish, 3.5 inches « 



Although the ratio of migrant sea lampreys to resident game 

 fish tal^en in the nets was high, none of the fish bore any evidence 

 of lamprey attacks except one 30.6-inch northern pike, tal-cen on May 

 29, indiich had an old, healed scar. However, on May 2I4., 19U7, a 

 smallraouth bass about li|. inches in total length f/hich carried a 

 large, fresh lamprey scar was seen swimming in shoal water^ Since 

 smallmouths migrate into the Ocqueoc vratershed from Lake Hur'on 

 during this season and since many individuals of game species taken 

 in the Carp Creek -vveir and trap were lamprey marked, it is quite 

 possible that this scarred fish may have been attacked on a recent 

 date "vrfiile in Iske Huron » 



One experimental gill net set for a 36-hour period in Ocqueoc 

 .Lake on April 21, 19^8^ yielded the following: 17 northern pike 

 averaging 19 » 7 inches; 2 rainbow trout averaging 15=3 inches; 

 1 largemouth bass of 11 oO inches; and 3 suckers averaging 12,6 

 inches o Again, none had lamprey marks. 



(6) Distance of migration 



In spite of the physiological drain of stream migration ivithout 

 feeding and the energj' demands of surmounting countless obstacles 

 of current and falls, sea lampreys travel considerable distsnces 

 upstream to reach suitable spawning grounds „ Approximated ma>:ima 



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