TRACKING THE EFFECTS OF THE ASIAN CLAM ON THE DIET OF FISHES IN TENNESSEE

Corbicula fluminea is a freshwater clam native to Southeast Asia that is now one of the most highly invasive species in freshwater ecosystems worldwide. The first documented occurrences of the Corbicula genus in North America were on Vancouver Island in 1924 and later in the Columbia River of Washington in 1938. The species spread along the Pacific coast of North America between 1938 and 1955, and specimens were found in the Ohio River in Kentucky in 1957. The first documented occurrence of the invasive clam in Tennessee waters was in 1959 in the Tennessee River in Hardin County. The purpose of this study is to examine the extent to which the diet of molluscivorous fish in Tennessee has changed since the introduction of the invasive clam Corbicula fluminea. The University of Tennessee Etnier Ichthyology Collection (UTEIC) houses the world’s largest collection of fish native to the southern Appalachians. With nearly half a million specimens, it is the largest collection of fish in Tennessee. Specimens in the collection date back to the 1960s, which roughly coincides with the introduction of the Corbicula fluminea to Tennessee waters. The introduction of a non-native species to an ecosystem generally leads to repercussions in the food web. We hope to trace the change in diet of molluscivorous fish after the introduction of Corbicula fluminea by analyzing the gut content of fish in the collection. Specimens used for the study will be chosen based on known molluscivory and the watershed in which each was collected. The gut contents will be documented as presence/absence of Corbicula fluminea and native mussels and volumetrically for detritus and aquatic insects. The preliminary results show that fish collected in the 1990s contain both native mussels and Corbicula fluminea. Further results will be presented documenting the occurrence or non-occurrence of Corbicula fluminea before the 1990’s. Our findings provide a good illustration of the value of historical data on the timing and spread on invasive species.