upon the location and season, smelt were caught 

 by handline and by dip, cast, bag, and gill nets. 

 Except for a few instances the same individuals 

 were examined for both PEN and G. hertwigi. For 

 evidence of PEN, live smelt were measured for 

 total length, and the caudal peduncle was wiped 

 free of water and mucus with a clean towel and 

 then severed and a smear made from a small drop 

 of blood placed on a clean slide. Smelt were sexed 

 and given a gross external and internal examina- 

 tion for evidence of G. hertwigi and other abnor- 

 malities. Microscopic examination of unstained 

 and Giemsa-stained spores from cysts was ini- 

 tially made to confirm the presence of G. hertwigi . 

 Air-dried blood smears were fixed in absolute 

 methanol for 3 min and stained with diluted 

 Giemsa for 30 min. Smears were examined 

 thoroughly under oil immersion at 1,000^ to de- 

 termine the presence of PEN. 



^:-/?^~'?:;w;y ' i 



• 



% 



•*• 



• # • 



'^ ' ..• 



Results 



PEN - Anadromous smelt — Of the anadromous 

 smelt sampled, 55. 7"^^ (786/1,412) were infected 

 with PEN (Table 1 1. By light microscopy, PEN 

 lesions of smelt red cells resemble those of EICDV 

 infected Atlantic cod (Figure 2). Infected smelt 

 occurred in every stream sampled (Figure 1 ). The 

 highest incidences were in Kingston (100/100), 

 Addison (lOQ/lOO), and Hingham (99/100). Lower 

 incidences were evident from Nova Scotia and 

 New Brunswick than from Maine, New Hamp- 

 shire, and Massachusetts. 



Individual infections were light; of the 786 in- 

 fected smelt, the highest infection was 8'f in a 

 smelt from Kingston. Overall, 87.7'7f (689/786) of 

 the infected smelt had <1.0% of their red cells 

 infected: 12.3'7f (97/786) had from 1 to m. 



The two areas with the highest incidences, 

 Kingston and Addison, also had the highest indi- 

 vidual infections and accounted for 87.Q'7( (85/97) 

 of the smelt in this study with V7c or more infected 

 erythrocytes. Kingston had 64/100 smelt with in- 

 fections >V7c\ Addison had 21/100. In contrast, 

 Hingham with an incidence of 99/100 had only- 

 four smelt with infections >V7c. From a total of 

 1,387 anadromous smelt sexed, 54. 3% of the males 

 and 58.39; of the females had PEN. 



PEN - Landlocked smelt — Damariscotta Lake 

 was the only lake with PEN infected smelt, 3.8'/f 

 (4/104). Individual infections were <\'7( . Because 

 of the design of the fishway at Damariscotta, ana- 



% 



< 



Figure 2. — Rainbow smelt erythrocytes with PEN lesions re- 

 sembling those of PEN (EICDV I infected Atlantic cod. Infected 

 cells show characteristic chromatin condensation and nuclear 

 degeneration. Unlike cod, cytoplasmic virions were not visible 

 by light microscopy in infected smelt erythrocytes. 



dromous smelt are unable to negotiate the 

 fishway leading into the lake. However, there is a 

 possibility that some of the smelt we sampled 

 could have been from a coastal population. Live 

 coastal smelt are used by ice fishermen as bait for 

 salmon and togue, and there is a possibility that 

 unused bait could have been released into the lake 

 with a resultant intermingling of coastal and 

 landlocked smelt. 



Glugea hertwigi -Anadromous smelt — Overall, 

 8.09f (135/1,692) of the anadromous smelt were 

 infected with G. hertwigi (Table 1). Infected smelt 

 occurred mail 16 coastal areas sampled (Figure 3). 

 Distinctive white, spherical cysts were found 

 primarily along the intestinal tract but often on 

 other internal organs such as liver and gonads. 

 Cysts varied from pinhead size to 5 mm (Figure 4). 

 Degree of infection varied from one cyst to severe 

 infections where the abdominal cavity was nearly 

 filled. Areas with highest incidences were at Kit- 

 tery 49';;- (20/41) and Kingston 289'^ (28/100). The 

 lowest incidence was at Boothbay with 0.9% ( 1/ 



505 



