Sampled localities and sites :: Image: Authors

Ballesteros, E., Marsinyach, E., Bagur, M., Sales, M., Movilla, J., Bolado, I. and Cefalì, M.E., 2020. The pearl oyster Pinctada imbricata radiata (Leach, 1814) (Bivalvia: Pteriidae) reaches Minorca, Balearic Islands. Boll. Soc. Hist. Nat. Balears, 63: 97-108. ISSN 0212-260X. e-ISSN 2444-8192. Palma (Illes Balears).

Abstract: We report on the presence of the pearl oyster Pinctada imbricata radiata (Leach, 1814) in two sheltered areas of the island of Minorca, Maó Harbour and Fornells Bay. Shallow depths (0-1.5 m) have been surveyed by free diving. Living oysters have been found in only 4 of the 22 surveyed sites, with densities ranging between 2.12 oysters·100 m-2 and 0.12 oysters·100 m-2, which indicates that the species is currently non-invasive. Average shell length in the observed specimens was 60.2 ± 13.9 mm (mean ± SD). According to the size of the oldest specimen found and the reports of a shellfish farmer from the Maó Harbour, date of introduction should be around year 2016. Since the introduction is recent, attention must be paid to the future spread of this species, regarding its high invasive capacity in several Eastern Mediterranean localities.

Keywords: Pearl oyster, Pinctada radiata, alien species, Minorca, Balearic Islands, Mediterranean Sea