Search

The occurrence of the invasive seaweedCaulerpa taxifoliain the Straits of Messina (Italy) provides an excellent opportunity to examine the spatial and temporal patterns of abundance of the endemic Mediterranean sacoglossanOxynoe olivacea.Densities of this species were recorded in March, June and October 2000 on three different habitats: the underside of boulders (UNB), the upper side of boulders (UPB), and the surface of concrete blocks (CB). Results showed that in March,O. olivaceawas consistently more abundant on UNB whereas in June it was present exclusively on CB. The density ofO. olivaceawas similar in the three habitats in October. The hiding behaviour ofO. olivaceaand its seeming disappearance in March did not coincide with a decline of abundance of phylloids ofC. taxifolia.The results represent an important basis for further studies devoted to the investigation of abundance of these marine invertebrates, which has been traditionally thought of as unpredictable. [ABSTRACT FROM PUBLISHER]