Migration and feeding in intertidal whelks, N. ostrina and N. lamellosa

Abstract

Our study seeks to gain more information on the migration and feeding patterns of two common intertidal carnivorous snails, Nucella lamellosa and Nucella ostrina. These whelks are native to the western coast of the United States ranging from California to Alaska and feed primarily on barnacles. The information from our study will be useful in determining some of the effects of global climate change on the intertidal ecosystem. Because of the predatory feeding pattern of these animals they are important in determining what else can live in the region. We gained more clarity on the patterns exhibited by these snails during the period between feeding peaks by observing the counts and densities within a plot on the shoreline as well as the movement of tagged individuals. We found that although there was no feeding peak during our study, and therefore no mass vertical migration, the N. lamellosa did appear to be feeding in a higher percentage higher up the shore. We also gained some insight into the effects of radio tagging on snail behavior when we discovered that that radio tagged N. lamellosa appeared lower on the shore than those without radio tags. This information will help further studies on whelks.