JOHNSON: MICROSPORIDANS OF AMPEUSCA AGASSIZI 



MARYLAND 



i^ZZ^^-^.'" CAPE 

 '^ • HATTERAS: 



^ ., ,76' 



50 100 150 200 



KILOMETERS 



Figure 1.— Benthic stations of Northeast Monitoring Program at which populations of gammaridean amphipods were sampled dimng 



the survey, 1980-82. 



and probably in a less populated area (Mills 1967) 

 or by emigrating juveniles (Bousfield 1973). Thus, 

 juveniles and perhaps ovigerous and postovigerous 

 females of A. agassizi and other species could at 

 times be immigrants into locations with already 

 established populations of older juveniles and 

 subadult males and females. 



Microsporidans of Ampelisca agassizi 



Most of the populations of A. agassizi sampled 

 were regularly infected by a species of microsporidan 

 that attacks the longitudinal pleosomal muscles 

 (Figs. 3, 4). Infected muscles were chalky white in 

 fully developed infection, and easily visible through 



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