450 VADAS, KESER, AND LARSON 



All but one of the direct effects on Ascophyllum were observed 

 in Montsweag Bay. The proposed neutral zone (the region between 

 gradual demise and enhancement) was not identifiable in our growth 

 data, if it exists at all. No attempt was made to identify all the direct 

 ecological effects in the field. Given the large variation in field data, 

 it is unlikely that moderate shading in the neutral zone could be 

 distinguished from normal variation, and it is questionable whether 

 increased shading could be detected in the enhancement zone. 

 Although we made no attempt to investigate indirect ecological 

 effects fully, the absence of potential competitors and colonization 

 by one warm-water alga were noted. We saw no evidence of 

 competitive displacement of the dominant organism, even though it 

 was severely stressed. Finally, it is questionable, given the generally 

 reduced number of species occurring in these and similar estuaries 

 (Mathieson and Fralick, 1973), whether any species besides Fucus 

 and a few small annuals could colonize the intertidal ledges of these 

 estuaries. 



ACKNOWLEDGMENTS 



Research reported here was supported by a grant from the Maine 

 Yankee Atomic Power Company. We acknowledge the assistance of 

 Steve Evans and Carroll Morse and the environmental studies group 

 at MYAPCO and the following students: Dennis Healy, Robin 

 Burrill, Heather Saunders, and William McCarthy. (Contribution 111, 

 Ira C. Darling Center, University of Maine, Walpole.) 



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