First record of the marine bryozoan Membranipora membranacea (Linnaeus, 1767) in South Africa

This study reports the first discovery of the alien marine bryozoan Membranipora membranacea (Linnaeus, 1767) from South Africa.In March 2024 two heavily encrusted Ecklonia maxima kelp plants washed up on Muizenberg beach in False Bay.Taxonomic investigation of the lacy white crust covering the fronds confirmed it to be M. membranacea.Kelp plants encrusted with this bryozoan again washed up in October 2024, suggesting that M. membranacea is established within the bay.As this species is known to foul hulls and has long-lived planktonic larvae, it was likely introduced to South Africa via ballast water.In other invaded ranges this species negatively impacts kelp forests causing mass kelp mortality, changing the structure and function of the affected ecosystem, and enabling the establishment of other non-native taxa.This highlights the threat posed by M. membranacea to ecologically and economically valuable kelp forests in South Africa.The discovery of this highly invasive bryozoan highlights the importance of routine monitoring for alien species along the South African coast.