Mediterranean Mussels are Tough Invaders:
By Brent Lockwood     Awards: Miller, Myers, Friends

The Mediterranean blue mussel, Mytilus galloprovincialis, is an invasive species that has been introduced by humans to coastal marine environments throughout the world. In this setting, M. galloprovincialis has negative impacts on native species. For example, in California M. galloprovincialis has supplanted our native blue mussel, Mytilus trossulus, over the southern end of its former range, from San Diego to Monterey Bay.   Why is the Mediterranean blue mussel so successful? Here in Dr. George Somero’s lab, we are investigating aspects of mussel physiology that make these Mediterranean mussels such tough invaders compared to their wimpy Californian cousins.

How a mussel responds to its environment is determined in large part by its physiology. Studies have shown that M. galloprovincialis grows faster and is more heat tolerant than M. trossulus. This helps to explain why the Mediterranean mussel has done particularly well in central and southern California, and yet our local mussel remains dominant at sites north of San Francisco Bay. 

We are interested in elucidating the molecular underpinnings of these physiological differences. In particular, we want to know what differences there are in the genes and proteins of these two mussel species. So far, we have found that the Mediterranean mussel has proteins that function better at high temperatures than those of the local mussel. We have also observed that the Mediterranean mussel has a greater ability to respond to heat stress by making certain proteins that maintain cellular homeostasis.

Our goal is to gain a more complete picture of how environmental factors influence organismal physiology and thereby limit the biogeographic distributions of invasive and native mussels on the California coast. By extension, we hope to be able to make predictions of how these species will respond to global climate change.

Blue mussel distributions on the West Coast. Mytilus galloprovincialis in pink. Mytilus trossulus in blue.