|
Generalized life cycle of the blue mussel: Sexes usually separate but some hermaphrodites may occur in population. Spawning occurs from March to October. Mass fertilization occurs in water column and larvae develop within several hours. Larvae remain planktonic for about 3-5 weeks and are dispersed by currents. At approximately 0.35 mm larvae settle from plankton. Primary settlement involves initial attachment to filamentous algae or hydroids. Secondary settlement occurs on adult clumps or on clear areas where firm attachment is made using byssus. Post-larval mussels use byssal threads as a "parachute" for transport by currents before attaching permanently to rocky or other hard surface. Adult mussels may grow to 80 mm, but in B.C. they seem relatively short lived and most appear to die after one spawning when they are typically 30-60 mm in length and 3-4 years old.