Distribution of Shore Algae on Shaw Island 



Walter C. Muenscher, 



Cornell University, Ithaca, N. Y. 



It has already been noted that the shores of the San Juan Islands are 

 very rich in algal vegetation. Many species have been recorded but care- 

 ful collecting constantly increases the list of marine algae found on these 

 islands. A careful study of the distribution of the algae of each island 

 would be required before this list may approximate completeness. This 

 kind of a survey would not only be useful locally to those interested in 

 investigations at the Puget Sound Marine Station, but would also be very 

 desirable for gaining a general knowledge of the distribution of the species 

 of the islands as compared with other localities. A careful study of dis- 

 tribution is also a prerequisite of many systematic problems of this lo- 

 cality. In a previous paper^ the writer grouped the shore algae of San 

 Juan Island into five associations as follows: 



Endocladia association 

 Fucus association 

 Ulva association 

 Laminariaceae association 

 Zostera association 



Since the general structure of the algal associations of Shaw Island and 

 San Juan Island is not so very different, the above paper^ may be used 

 as a basis for the present paper. The purpose of this paper is to discuss 

 the distribution of the shore algae of Shaw Island and to record such 

 notes on distribution as may be helpful to investigators and collectors in 



this region. 



Shaw Island is located east of San Juan Island. Its center is about 

 latitude 48° 3i' and longtitude 122° 58'. It is separated from San Juan 

 Island on the west by San Juan Channel; on the south and east from 

 Lopez Island by Upright Channel; on the north from Orcas and Crane 

 Islands by Harney Channel and Wasp Pass (plate 34). Shaw Island is 

 the geographic center of the San Juan group. It is protected from the 

 larger open bodies of water by other islands, but the tidal currents are 

 very strong in some of the narrow channels about it. 



In the present work several small islands that lie close to Shaw Island 

 are included. Among these may be mentioned Canoe Island, off the south- 



iMuenscher. Walter L. C. A. Study of the Algal Associations of San .Juan 

 Island. Puget Sound Marine Station Pub. 1: 59-84. 1915. 



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