Perna perna Linnaeus, 1758

An invading mussel may impact at least some features of the community structure. In Uruguay, where P. perna invaded beds of the smaller native Brachidontes rodriguezii (d’Orbigny, 1842), it forms a significant part of the biomass and outnumbered B. rodriguezii at the lower intertidal (Carranza and Borthagaray 2009). In southern Brazil, the native whelks (Stramonita spp.) prey on P. perna, and it is probably a significant food resource for crabs and fishes (Fofonoff et al. 2018). Levantine beds of intertidal mytilids underwent a rapid shift in the 1990s (Galil 2007), when the invasive Erythraean (native to the Red Sea) Brachidontes pharaonis (P. Fischer, 1870) displaced the previously abundant native mytilid Mytilaster minimus (Poli, 1795). Owing to its larger size compared with the native M. minimus (max. 12 mm shell length) and B. pharaonis (max. 40 mm shell length), P. perna, if established, may cause changes to the ecology of the Levantine mussel beds. Indeed, change is already apparent: the dense beds of P. perna off the Israeli coast enhanced the population of the local whelk Stramonita haemastoma (Linnaeus, 1767)