United States Department of the Interior, Oscar L. Chapman, Secretary 

 Fish and Wildlife Service, Albert M. Day, Director 



Fishery Leaflet 360 



FE 



Washington 25. D.C. February 1950 



SEA LAMPREYS 07 TEE ATLANTIC COAST AND GREAT LAKES 



By Lola Tidwell Deee 

 Branch of Fishery Biology 



The sea lamprey ( Petrom.vzon marinus ). known also as great sea 

 lamprey, river lamprey, green lamprey, lake lamprey (landlocked form), 

 shad lamprey, lamper-eel, lamphrey-eel, sucker, and nine-eyes, is found 

 in Vdcere of tenreerate and subarctic latitudes nearly all over the world 

 except in southern Africa. The adult lamprey, once found only in marine 

 waters, has become well established in the Great Lakes and in the lakes 

 of western and northern New York. 



This vertebrate, shaped like an eel but unrelated to it, has a 

 smooth, scaleless body. Its maximum length is three feet, and its great- 

 est weight is two pounds or more. The upper part of the adult, spawning 

 lam-orey ie mottled bluish, brownish, or blackish upon a gray or yellow 

 background; the lover part whitish or grayish. If a lamprey ie less than 

 a foot in length, it is not mottled. Its two dorsal fins are separate. 

 Close behind the eye of the adult on each side is a row of seven nearly 

 circular gill openings through which the lamprey breathes. These open 

 internally into a canal below the esophagus and communicating vdth it 

 near the mouth. The single nostril, on top of the head, is a blind sac 

 Instead of a mouth with Jaws, the lamprey has a round sucking disc, 

 from the center of which rows of sharp, horny teeth radiate in all direc- 

 tions. (Figure l) One to three larger teeth are on the palate. The 

 tongue is file-like. 



Lampreys attain their full growth in the Atlantic Ocean and 

 the lakes, where they gorge for an unknown number of years on the blood 

 and body fluidB of fishes. Becoming sexually mature there, they migrate 

 in large numbers in spring or early summer into streams and rivers to 

 spawn. When a spawning movement ie under way, these parasites, not feed- 

 ing actively, make their heaviest migrations during darkness; before the 

 peak of a run males predominate; after thr peak, female 8.1/ While en 



1/ Vernon C. Applegate, The Menace of the Sea Lamprey, Michigan Con- 

 servation, May 19^7. Vol. XVI, No. '4, pp. 6, 7, 10. 



