for present loio-wn spaivning (grounds show a range of from 19 to 

 k9 miles. Obviouslj this fish is capable of penetrating well 

 toward the headxmters of most Michigan tributaries of the 

 Great Lakes, unless blocked by barrier falls or dams. Exemplary 

 distances from the Great Lalces shoreline to nesting areas follow: 



Region 1. ( Upper Peninsula ) 



Sturgeon River, Alger County 39.0 miles 



Trout Brook, Chippewa County 22 . ^ miles 



Region 2. ( Lower Peninsula ) 



Ocqueoc River, Presque Isle County 19.0 miles 



Au Gres V/atershed: 



Kale Creek, Iosco County 3U.0 miles 



Hope Creek, Iosco County 2^.5 miles 



E. Br. Au Gres River, Iosco County 23.0 miles 



Au Gres Pdver, Iosco County 2I4..O miles 



Rifle River, Ogemaw County 39.0 miles 



Houghton Creek, Ogemaw County Ul?. m.iles 



Little So. Br. Pere Earqustte, Lalce County U7.0 miles 



Baldwin Creek, Lake County US . miles 



Bear Creek, Manistee County 32.0 miles 



(7) Patholo^, parasitism , and predation 



(a) Pathology 



or ^,13^ sexually mature, mi<-Taiit sea lampreys exar;.ined in 

 I9U7 and I9I4.3, none displayed any macroscopic evidence of either 

 bacterial or sporozoan induced infections, at least insofar as any 

 such disease vrould exhibit itself by internal or external inflam- 

 iTiations, ulcerous tissue, other obvious pathological conditions of 

 the viscera, or by abnormal behavior. 



In the samples examined, hovraver, there were a fevr individuals 

 which displayed developmental or structural abnormalities such as 

 those tihich ordinarily appear in any population of vertebrates. 

 In the Carp Creek spaivning run in 19U7 (1,599 specimens examined), 

 3 sea lampreys (2 males, I7.I and 18. U inches in total length j 1 

 female, Ih^l inches in total length) had deformed caudal fins. A 

 fourth specLnen (male, 16. L inches in total length) had a deformed 

 second dorsal fin. One male sea lamprey was taken which Tra.s gro- 

 tesquely short in body length in relation to its girth and other 

 bodily development. The lai^gest sea lamprey captured in 19^7^ a 

 female, 22.6 inches in total length (v/eight: I1.36 grams), possessed 



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