Particulate organic matter is the major food source of many filter-feeding bivalves including C. meridionalis.

Choromytilus meridionalis utilizes bacteria as a nitrogen resource, which is important for its growth and survival in the intertidal zone.

In the False Bay area, Choromytilus meridionalis all reproduce at the same time and partake in two breeding seasons.

The sexes are separate and females may be distinguished by the chocolate-brown color of the ovary, while the testis is yellow to white, depending on its state of development.

[6] This species is found in lagoonal, coastal, inner shelf, outer shelf, oceanic, brackish, seawater This species is found only around the southern African coast, from central Namibia to Port Elizabeth, in the sublittoral and lower littoral of rocky areas.

[8] This is due to rising anthropogenic climate change and urban runoff that is threatening the future of mussel farming.