Measuring Differences in Clam Populations between Two Stream Outflow Areas in False Bay, San Juan Island, Washington

Abstract

False Bay, an estuary mudflat located on San Juan Island, Washington has not been studied extensively in the past but is a home to many infaunal species, such as clams. In this study, I focused on the sedimentary effects that two different streams, False Bay Creek and Forest Creek, may have on the clam populations found in both stream outflow areas. I went to False Bay in the month of November and walked along five transects per stream outflow area, sampling for clams and sediment. Clam species were later identified and measured for height and length, and each sediment sample was sieved to determine volumetric proportions of sediment size. The results showed that the clam species Macoma nasuta was the most abundant species in the majority of the Forest Creek area and at the farthest region from the False Bay Creek stream. False Bay Creek had the highest abundance of diverse clam species when compared to Forest Creek. In addition, sediment size was smaller overall in the Forest Creek stream area and shows that there are other natural factors besides man made obstructions affecting sediment transport of both streams. This study is setting a baseline for future studies looking into how developmental changes to both streams could affect clam populations in False Bay.