The first record of an invasive mussel species in West Africa arriving from the Bijagós archipelago, Guinea-Bissau

During a recent field mission to the Bijagós archipelago*, in January 2018, a team from the University of Lisbon, described the first record of the Asian date mussel (Arcuatula senhousia) for the whole West Africa. A single individual was collected during benthos sampling at the northern mudflats of Bubaque island. This bivalve originates from the north-western Pacific, from Siberia to Singapore, including Japan.

It was accidentally introduced in several regions, far from its native area, such as in the western coast of North America, New Zealand and Australia, and the Mediterranean. Previous introductions are likely to have occurred from accidental transportation with oysters and other bivalves traded for shellfish farming or due to transfer in the ballast water of ships. The later may explain the arrival of the mussel at the Bijagós, as both fishing and cargo ships from East Asia regularly cross the waters and visit the ports of Guinea-Bissau. Invasive species are known to dramatically impact native communities.

Monitoring studies should thus be targeted to first confirm whether there is a self-maintaining population of the Asian date mussel in the Bijagós. If so, it will be critical to evaluate potential impacts of this invasive species upon the local benthic assemblages, which support an internationally relevant wintering community of migratory shorebirds. * This research was conducted in the scope of the project “Waders of the Bijagós: Securing the ecological integrity of the Bijagos archipelago as a key site for waders along the East Atlantic Flyway” coordinated by IBAP and funded by MAVA Foundation.