Mytilidae

Mytilidae, commonly known as true mussels, is a diverse family of marine bivalve molluscs in the order Mytilida. Members are typically elongated, laterally compressed shells that are dark in color and hinged along the posterior edge. Adults attach themselves to solid substrates by numerous byssal threads secreted by a gland in the foot, enabling tight clumping in colonies. They are filter feeders, drawing water through inhalant siphons to extract phytoplankton and detritus, and expelling water through exhalant siphons.

Geographically, mytilids have a cosmopolitan distribution, inhabiting temperate and tropical seas worldwide. They occur from the intertidal zone to deeper subtidal habitats, and some deep-sea relatives live around hydrothermal vents. The family includes numerous genera, most notably Mytilus (blue mussels) and Perna (green-lipped mussels), with other well-known groups including Modiolus and Bathymodiolus.

Reproduction is typically sexual, with many species releasing eggs and sperm into the water column (broadcast spawning). Fertilization is external, and the resulting trochophore and veliger larvae are planktonic before settling as juvenile mussels. Growth is slow, and individuals may live several years in suitable conditions. Many species form dense beds that provide habitat for other organisms and influence local ecology.

Economic and ecological importance: true mussels are among the world’s most important shellfish for food and aquaculture. Species such as Mytilus edulis, M. galloprovincialis, and Perna canaliculus support large fisheries and farming operations. Some Mytilus species have become invasive in non-native regions, where they compete with local fauna and alter habitats.

Conservation and threats: Mytilidae faces pressures from overharvesting, pollution, habitat modification, and ocean acidification, which weaken shells. Management measures include harvest quotas, selective breeding in aquaculture, and monitoring of invasive populations.