The broadcast spawning Caribbean shipworm, Teredothyra dominicensis (Bivalvia, Teredinidae), has invaded and become established in the eastern Mediterranean Sea

Abstract

Teredinids, commonly referred to as shipworms, are wood-boring bivalves estimated to cause over one billion dollars’ worth of damage to submerged wooden structures per annum. This paper reports the detection and establishment of the Caribbean shipworm Teredothyra dominicensis (Bivalvia, Teredinidae) in the eastern Mediterranean Sea. Identification was confirmed using an integrative taxonomical approach combining morphology, morphometry and molecular markers (COI-5P and 18S), thus improving both the taxonomic resolution and tractability of this invasive species. Sequence comparisons between indigenous Caribbean and Mediterranean specimens were at least 99 % identical. Wooden panels placed at the site of discovery were infested exclusively by T. dominicensis with specimens of varying size and age, indicating multiple settlement events and the presence of breeding populations in the region. Anatomical and behavioural observations confirm the species as a broadcast spawner with larvae undergoing planktotrophic development, thus distribution range is potentially extensive. Of the possible introduction vectors, transport via ballast water is proposed as the most likely. The establishment of breeding populations of a tropical teredinid in the Mediterranean is of considerable concern as tropical species are particularly destructive and degrade wood more rapidly than the species currently found in the region. This threat is likely to increase in severity due to global warming, as increases in temperature and salinity may lead to an increase in the distribution range, development rate and boring activity of teredinids.