First record of Dosima fascicularis (Ellis & Solander, 1786) (Crustacea, Cirripedia) in the Strait of Messina (Central Mediterranean Sea)

Dosima fascicularis (Ellis & Solander, 1786) is a pleustonic goose barnacle species. This species uniquely constructs its own float using flotsam, such as floating tar balls, plastic particles and other small items, as attachment surfaces (Darwin 1852; Minchin 1996; Ryan & Branch 2012; Junoy & Junoy 2014). The species is also an important constituent of the ocean surface macrofauna, commonly referred to as ‘blue plankton’, that also includes a few species of molluscs (e.g. Janthina) and hydrozoans (e.g. Velella, Physalia and Porpita) (Betti et al. 2017). Dosima fascicularis is widespread in subtropical ocean waters from the North Atlantic to the Baltic Sea (Darwin 1852) but is rare along the European ocean coast (O’Riordan 1967; Cotton et al. 2006; Turk 1982). Information regarding the blue goose barnacle is sparse, with records often based on stranding events, which occur under singular oceanographic and climatic conditions that cast pleustonic organisms ashore (Cheng & Lewin 1976; Minchin 1996; Liss & Duce 1997). The species has been reported from the Mediterranean, the first record being from Maltese waters (Mifsud 2005) and the second from Ligurian shores (western Mediterranean), together with a large number of Vellela velella and Janthina pallida (Betti et al. 2017). More recently, Mokrane et al. (2019) reported five specimens from Algerian waters. In the present paper, four specimens of Dosima fascicularis are documented, found stranded along the Sicilian coasts of the Strait of Messina (Central Mediterranean Sea). In this area, the shore stranding of deep-water marine organisms belonging to different taxa is a recurrent phenomenon, due to the prevailing hydrographic conditions (Cavallaro et al. 2017; Battaglia et al. 2017)