Harvesting

The mussels are harvested after attaining a size of 80-100 mm with in a period of six months. Indication of good mussel could be measured by the condition index, which is the ratio of wet meat weight to the total weight of the mussel. The condition index shows seasonal changes and is usually related to reproductive cycle. It is generally high before spawning. The wet meat normally forms 33 to 40% of the total weight in mussel as found in different experiments.

Harvesting of blue mussels for market requires that the product be removed from the longlines and the shells cleaned of external fouling before presentation. This process is usually automated and involves a washer-tumbler machine in which the mussels are rotated and rubbed against each other to dislodge small mussels, barnacles and other fouling organisms. In some ideal growing areas where there are high levels of nutrients and phytoplankton, the mussels need to be transferred to more oceanic water to clean them before harvesting.