Date of Award

Fall 2009

Project Type


Program or Major


Degree Name

Master of Science

First Advisor

James E Byers


Epibiosis, or the growth of one organism on another, is a common life history strategy in marine environments where space is at a premium. Many epibiotic organisms live on or in biotic hard substrates, such as shells. In the spatially competitive rocky intertidal of New England, hard substrate surface area is greatly increased by the presence of the non-native marine periwinkle snail Littorina littorea. The snail's shell can be exploited by epibiotic organisms such as barnacles, bryozoans, and encrusting calcareous algae. However, an in-depth examination of the prevalence and impact of epibionts on Littorina littorea in New England has not been done to date.

In Chapter 1 of this thesis, I examine the distribution and prevalence of epibionts on Littorina littorea and other gastropod species in northern New England at four different tidal heights from Maine to Massachusetts. I then focus on local scale factors influencing patterns of distribution and abundance in the most common taxa of epibionts, encrusting calcareous red algae, in Chapter 2. In the final chapter, I examine the impact of algal fouling on Littorina littorea's physiological parameters, grazing rates, movement patterns, predation susceptibility, and survival.