Endemic to New Zealand, the green-lipped mussel lives mostly below the intertidal zone, and its emerald shell can grow up to 24 centimetres long.
Green-lipped mussel larvae can swim on ocean currents for hundreds of kilometres. After about six weeks of free-swimming larval life, they attach to a surface with their byssal threads and become spat. Spat can still move around on their foot, or drift, using their threads as parachutes.
Mussels filter a large amount of water through their gills to trap phytoplankton, which they transfer to their mouths. Sometimes pea crabs live inside the mussel’s shell and steal plankton from its gills. Crabs have been observed getting inside the shell by stroking it, so it opens wider.