Now you see it now you don't : presence of Caulerpa racemosa var. cylindracea (Chlorophyta, Caulerpales) in the Maltese Islands

Abstract

Caulerpa racemosa var. cylindracea, an invasive alga present in the Mediterranean Sea, was first recorded from the Maltese Islands in 1997. Between then and the mid-2000s, the alga spread rapidly and became abundant at most coastal sites around the islands. However, its spatial distribution and abundance decreased rapidly after 2006, such that the alga has become rare to encounter locally. The present work, which formed part of a broader study to assess the influence of C. racemosa on hard bottom infralittoral habitats, confirms a large decline in the distribution and abundance of this species in recent years in Maltese coastal waters.