73 



Overall, the Westport River has the most complex history of 

 changing eelgrass abundance of any site studied in Buzzards Bay. The 

 shallow bathymetry in this estuary make eelgrass populations susceptible 

 to storms and ice scour, and likely accounts for the wide fluctuations 

 in eelgrass cover observed. This pattern is markedly different from bed 

 recolonization on the outer coast which typically show continuous 

 expansion over decades. 



Changes in bed cover around some areas like Bailey Flat (Fig. 2) 

 can be explained by migrating shoals, storms and ice scouring. Other 

 changes, like the migrating upper estuarine limit of eelgrass growth 

 (Fig. 1) , and the general decline in eelgrass abundance in the upper 

 part of the estuary since the 1940' s and 1950 's are likely due to other 

 causes such as nutrient loading. For example, benthic algae and 

 eelgrass algal epiphytes become more conspicuous as one moves northward 

 into the West Branch. Near the mouth, the depth of eelgrass growth is 

 2.5 m whereas east of Sanford Flat, eelgrass grows to less than 0.5 

 meters. Shellfish beds in the north end of the East Branch have been 

 closed due to high fecal coliform counts, and elsewhere bacterial inputs 

 are usually associated with nutrient inputs. Together, these facts 

 suggest that nutrient loading is becoming problematic in the Westport 

 Rivers, and needs further study. 



Given the importance of this estuary, a more comprehensive 

 understanding of the changing eelgrass abundance there is desirable. 

 Periodic photographic surveys should be taken under favorable conditions 

 during several growing seasons, and damage from storms and ice scouring 

 should be monitored. Historical changes in distribution and abundance 



