93 



were tied to a new sewer system that er^ptied into a neighboring bay. 

 This "iiay have led to water quality improvenents , and new expansion of 

 eelgrass by 1981. This explanation see-^ns more plausible that declines 

 due to disease, because most of the losses occurred at the deeper 

 margins of beds, which suggests declining light availability, and 

 because beds closer to the mouth of the Bay expanded or remained static 

 during the same period. 



Great Neck, Wareham and the 'Tareha.n River Estuary 



The waters off Great Neck are moderately well flushed, in part due 

 to water exchange in the Cape Cod Canal, and the shoreline somewhat 

 exposed. A shallow shelf less than 4 m MLW covers more than 300 ha 

 offshore. Today eelgrass is extensive on these shallows. 



The earliest photographs obtained (a 1956 aerial survey and 

 fragmentary coverage from 1944 and 1951) show that eelgrass was absent 

 from most areas, except for a large and conspicuous bed around Little 

 Bird Island {Fig. 11) . Because this bed is isolated, and little 

 eelgrass is present onshore at this time, this population may have 

 survived the wasting disease. These beds colonized the western lobe of 

 Great Neck during the early fifties, then migrated eastward along Great 

 Neck between 1955 and 1960 (Fig. 11). 



The onset of colonization south of Long Beach occurred at least 10 

 years earlier than colonization on the shoal south of Indian Neck, 1.5 

 km to the east, where the first beds appeared in 1958 (Fig. 12). These 

 beds expanded greatly, and by 1966, the population had nearly reached 

 peak cover. 



