Recent spreading of Xandarovula patula (Mollusca: Gastropoda: Ovulidae) towards the central North Sea suggests a link to rising water temperatures

Abstract

The carnivorous gastropod Xandarovula patula is a species being known to mainly occur west and south-west of the UK, down to the Atlantic coast of Spain. It also was recently reported from the central parts and the periphery of the North Sea, up to Trondheim (Norway). Now, it was also recorded during a survey of the epibenthic faunal composition from the Dogger Bank in winter 2011. The collecting stations are located on a routine station on the western Dogger Bank at a depth average of 25 m, as well as off the south-western edge of the Dogger Bank at a mean depth of 65 m. The bottom of both stations is covered with sparse boulders and rubble with a dense cover of Alcyonium digitatum, the preferred food of Xandarovula patula. This is another example for the spreading of oceanic 'warm water' species towards the central North Sea along the main, northern currents. The present work summarizes all records of X. patula from the North Sea available in the literature up-to-date and verifies rising water temperatures at the main area of recent records at the Dogger Bank, possibly promoting the species' spreading.