(full paper is archived in the Miller Library)
Title: The sand crab Emerita analoga as an indicator of DDT levels in a littoral marine environment
Student Author(s): Laughton, Craig W.
Faculty Advisor(s): Lee, Welton
Location: Final Papers Biology 175H
Date: June 1971
Keywords: marine pollution
Abstract: In an effort to determine the effectiveness of the sand crab, Emerita analoga, as an indicator species of DDT levels in the California coastal marine environment, specimens were collected from different beaches on Monterey Bay and analyzed using gas-liquid chromatography (GLC). After all initial samples were analyed, it was found that ovigerous animals contained much lower levels of DDT than non-ovigerous animals. Since the bulk of the samples for the different beaches had differing proportions of ovigerous to non-ovigerous anumals, and this difference was not recorded, the effectiveness of this species as an indicator of DDT was not fully demonstrated. However, the specimens collected do represent natural populations from the various beaches, and a rough comparison is possible. Since DDE is reported to increase with time in a biological system, the relative amount of DDE to the total residues of DDT was determined for each beach and the data was analyzed for possible trends. Sand samples were also collected at each beach, when the Emerita were collected, and comparison of DDT levels in the sand with those in the animals made.