RESULTS AND DISCUSSION 



MUSSEL DENSITIES IN FLEETED AND UNFLEETED AREAS 



We quantitatively sampled a total of 274 0.5-m quadrats 

 along five transects in the fleeting site (Figure 2) . Results 



for each transect are presented in Appendix B. Densities in 



o 

 samples ranged from to 44 live mussels/m . Mean densities 



(with standard deviations) were calculated for each transect 



(Table 1) and were extremely variable. Mean transect densities 



(and standard deviations) in the fleeting area ranged from 1.2 8 ( + 



2.48) to 13.24 (+ 10.06) mussels/m , with an overall mean of 7.10 

 (+ 8.62) . 



Seventy-seven 0.5-m samples were collected along one 



transect in the downstream control area (Figure 1) . Data for each 



transect are listed in Appendix B and summarized in Table 1. 



Densities ranged from to 32 live mussels/m , and the mean 



density (and standard deviation) was 11.46 (+8.56). There were 



2 

 more live mussels/m , on average, in the unfleeted control area 



than in the fleeted area. Variances were approximately equal in 



the two areas*. F 



EFFECTS OF BOATS ON MUSSEL CORRALS AND SUBSTRATE 



We placed 24 mussel corrals in June 1984 (Table 2) . When we 

 returned in October 1985, and tried to locate the corrals placed 

 in the experimental plot where barges had been grounded, we found 



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