The blue mussel is the common name for Mytilus edulis or M. galloprovincialis, mussels of high commercial value. Distributed worldwide in temperate coastal waters, they are filter feeders that accumulate biotoxins, heavy metals, and pathogens, so harvesting is restricted to classified, monitored waters. High demand means wild harvests are supplemented by aquaculture, chiefly rope and bottom culture that also eases pressure on wild beds. They must be cooked until shells open, with unopened ones discarded, and raw consumption is restricted to the safest classified areas. Affordable, nutritious, and sustainable when well managed, they are a staple European shellfish.