Shrinking Conch (image) Smithsonian Tropical Research Institute Caption Prehistoric fighting conch Strombus puglis (L) and modern shells of the same species (R) show how the shellfish has decreased in size over time. Credit Smithsonian Tropical Research Institute/Courtesy of Aaron O'Dea Usage Restrictions Credit Smithsonian Tropical Research Institute. Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.