LAMPREY FAMILY (Petromyzonidae) 

 SEA LAMPREY 



Petromyzon marinus Linnaeus 



The sea lamprey, representing a primitive group of fishes, is eel-like in 

 appearance with a soft, cartilaginous skeleton. The general range is the Atlantic 

 coasts of Europe and North America from Labrador south to Florida in the 

 Western Atlantic. In recent years they have become "landlocked" in the Great 

 Lakes basin. The distribution in Maine is confined to the coastal rivers and their 

 tributaries. 



Their adult life is spent in marine waters returning to fresh-water streams 

 to spawn during May and early June. As the spawning time approaches the 

 intestine atrophies and the entire animal becomes a reproductive machine. It 

 seems unlikely that they do any damage to other fishes during this period. Ap- 

 parently the bulk of the spawning runs moves up the streams after midnight 

 and before daylight although stragglers are observed at all times. The mature 

 adults continue up the streams seeking a suitable riffle area where they build 

 their nests in shallow water. It is thought that the males make their way up 

 the streams first and probably do most of the nest construction carrying stones in 

 their sucking mouths. After the female arrives in the spawning area she may 

 or may not help with the nest. The nest completed the male grasps the female 

 behind the head and wrapping his body around hers shakes vigorously. The 

 non-adhesive eggs are released and fertilized. A single female may have up to 

 235,000 eggs. After spawning the adults drift downstream to die. 



Several days later larval lampreys, called ammocoetes in this stage, emerge 

 from the nest and proceed downstream seeking a spot where the gradient has 

 leveled off. Here they burrow into a mud bank. The nonparasitic larvae feed 

 for from three to five years on organic material which they strain from the water. 

 At the end of this larval period at a length of four to six inches they transform 

 into the adult stage losing the fringe of cirri, the eyes come to the surface and 

 the horny teeth with the rasping tongue are developed together with the anti- 

 coagulant secreting glands. This transformation takes about two months. Along 

 the coast of Maine these newly transformed lampreys begin their migration to 

 the sea in the fall before the streams are frozen. Little is known about their 

 range in the ocean. Here the lamprey eel feeds parasitically on other fishes 

 hanging on with its sucking mouth and rasping with its tongue to obtain nourish- 

 ment in the form of blood and body fluids of the unfortunate victim. After 

 several years of this parasitic life the lamprey becomes mature and begins the 

 spawning migration back to fresh water completing the life history. The entire 

 cycle may take from five to eight years. 



The average adult running the streams of Maine is from two to two and 

 one-half feet in length although exceptional lengths of three feet have been 

 observed. 



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