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Cold Temperature Effects on Byssal Thread
Production by the Native Mussel Geukensia demissa
versus the Non-Native Mussel Mytella charruana

By: Sasha Brodsky | Mentors: Dr. Linda Walters, Dr. Kimberly Schneider, and Dr. Eric Hoffman

Abstract

Mytella charruana is a Central/South American mussel that has been found as an introduced species along the southeastern Atlantic coast of the United States since 2004. Previous experiments have determined the lethal thermal minimum of M. charruana to be between 6-9° C. Continuous byssal thread production is essential for mussel survival as it is used for attachment to substrates in natural environments, but may decrease when environmental conditions deviate from their optimum. We sought to determine whether M. charruana exhibits a non-lethal, thermal response involving a reduction in byssal thread production. Mytella charruana and, for comparison, a native mussel species, Geukensia demissa, were collected for this study. Water temperature was manipulated with chillers to near lethal temperatures (10°, 13° C) and newly produced byssal threads of all mussels were counted and cut daily for seven days. Both mussel species had lower byssal thread production at the colder tested temperatures (10°, 13° C) than in the control (23° C). However, G. demissa produced some threads at 10° C while M. charruana produced none. Also, G. demissa showed no difference in mean byssal thread production between 13° and 23° C. Mytella charruana had significantly fewer byssal threads at 13° C than at 23° C. Our results suggest that G. demissa can withstand colder temperatures than M. charruana, owing to their increased ability to produce byssal threads at lower temperatures. These results have implications for the survival and future spread of non-native M. charruana.

KEY WORDS: invasive species, marine mussels, byssal threads, thermal limits, temperature

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