Blue mussels have a minor spawning period in June, followed by a second, extended spawning period from August to January. The fertilised eggs are planktonic, averaging 0.07mm in diameter and develop into unshelled larvae within a day. Larvae are free swimming and the planktonic stage can last from 2 weeks to several months, although most larvae settle 3-4 weeks after spawning. Blue mussels are filter feeders, straining plankton from the water. They are preyed on by crabs, starfish, leatherjackets, pufferfish and flat worms.
Blue mussels are an important commercial fishery.
There are only small sectors still harvesting wild mussels. Most mussels are aquacultured, grown using long line methods, with sprat collected via natural settlement. All farmed product is sold live and whole in the shell. Today, mussels are grown at 20 of the lease sites granted in Victoria's Port Phillip Bay. The mussels are grown on ropes in clean, flowing ocean currents and harvested at their peak condition.