Blue Mussel - Larval Development

Larval Development

Larval development can last from 15 to 35 days depending environmental conditions including salinity and temperature, as well as location. Larvea originating from Connecticut mature normally at 15–20 °C, though at 15 °C normal development occurs at salinities between 15 and 35 ppt and 20 at 35 ppt at 20 °C.

The first stage of development is the ciliated embryo, which in 24-hours for fertilization form the trochophore. At this point although mobile, it is still reliant on the yolk for nutrients. Characterized by a functional mouth and alimentary canal the veliger stage also has cilia which are used for filtering food as well as propulsion. A thin translucent shell is secreted by the shell gland forming the notable straight hinge of the prodissoconch I shell. The veliger continues to mature forming the prodissoconch II shell. In the end stage of veliger development photosensitive eye spots and elongated foot with a byssal gland are formed.

Once the pediveliger is fully developed, its foot extends and makes contact with substrate. The initial contact with the substrate is loose, if the suitable the larva will metamorphoses into the juvenile form, plantigrade, and attach byssus threads. The mussel will remain in the state until reaching 1-1.5mm in length. This attachment is the prerequisite for the foundation for the blue mussel population. In sheltered environments large masses sometimes form beds which offer shelter and food for other invertebrates. Byssal thread are secreted by byssal glands located in the foot of the mussel, and are made up of polyphenolic proteins are proteins which serve as a bioadhesive.