reasons may be related to the vulnerability of 

 juveniles as discussed above. 



To insure success with transplanting tech- 

 niques, it is essential to reduce mortality among 

 transplanted clams either by protecting them 

 from significant sources of mortality in the field 

 or by retaining them in protective "nurseries" 

 until they pass this critical phase. Past attempts 

 to protect juveniles in the field by building fences 

 to exclude predators have proven costly, difficult 

 to carry out, and unreliable (Smith et al. 1955). 

 More promising are recent advances in aqua- 

 culture techniques for commercially important 

 bivalves. By employing "nurseries" for the young 

 and field "grow-out" procedures for adults, 

 sources of juvenile mortality can be reduced while 

 still utilizing natural sources of food during the 

 greater part of the individual's growth period. 



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 BROUSSEAU, D. J. 



1978a. Spawning cycle, fecundity, and recruitment in a 

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 1978b. Population dynamics of the soft-shell clam Mya 

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Caswell. H. 



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1970. Age specificity and ecological theory. Ecology 51: 

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FISHER, R. A. 



1958. The genetical theory of natural selection. 2d ed. 

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Hamilton, W. D. 



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DIANE J. BROUSSEAU 



Department of Biology 

 Fairfield University 

 Fairfield, CT 06430 



Department of Mathematics 

 Fairfield University 

 Fairfield, CT 06430 



JENNY A. BAGLIVO 



THE OCCURRENCE OF PISCINE 



ERYTHROCYTIC NECROSIS (PEN) IN 



THE SEA LAMPREY PETROMYZON MARINUS, 



FROM SEVERAL MAINE LOCALITIES 



The sea lamprey, Petromyzon marinus, is an 

 anadromous fish found in the North Atlantic 

 Ocean from Iceland and northern Europe to 

 northwestern Africa, and from the Grand Banks 

 and the Gulf of St. Lawrence to Florida (Hubbs 

 and Lagler 1949). The sea lamprey has adopted 

 an entirely freshwater life cycle in the Great 

 Lakes where it has seriously depleted fish popu- 

 lations (Everhart 1976). 



The lamprey feeds on other fishes by hanging 

 on with its sucking mouth. Once attached, it 



FISHERY BULLETIN: VOL. 82, NO. 3, 1984. 



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