Reciprocal Boccardia (Annelida, Spionidae) invasions in North and South America

RADASHEVSKY V. I.; J. M. ORENSANZ; DIEZ M. E.; HARRIS LESLIE H. ; CHAPMAN JOHN W.

Sydney

Congreso; 11th International Polychaete Conference; 2013

Australian Museum

The California mudworm Boccardia proboscidea Hartman, 1940, is widely reported in North America from British Columbia south to California, and, in the western Pacific, from Japan, Korea, China, Australia, Tasmania and New Zealand. Boccardia proboscidea is a likely introduction to Hawaii and South Africa and possibly northern Spain and England. The species is unknown from the northwest Atlantic or southeast Pacific but appears to have been recently introduced to the southwest Atlantic, as larvae in ballast water or by other mechanisms. An explosive development of B. proboscidea, discovered near the sewage outfall of Mar del Plata city, Buenos Aires Province, Argentina in 2008, was followed by intertidal populations discovered all along the coast of northern Patagonia, Chubut Province in 2010. These Patagonian populations produce dense beds of silty tubes in muddy substrata or bore into friable cyneritic sedimentites where they greatly alter the native communities. Progressive invasions of B. proboscidea in Argentina are accompanied by an apparent decline of its close relative, Boccardia claparedei (Kinberg, 1866) which occupies the same ecological niche. Boccardia claparedei is native to Brazil, Chile and Argentina and was previously unknown outside of South America. However, dense colonies of B. claparedei were discovered in 2010 and 2012 in sea-water drains of the Hatfield Marine Science Center, and the Oregon Coast Aquarium that flow into Yaquina Bay, Newport, Oregon, USA. Despite massive larval production by the drain channel populations, adult B. claparedei have not been found in Yaquina Bay. Moreover, Yaquina Bay remains densely populated by B. proboscidea. Boccardia claparedei is a likely introduction to Oregon as a hitchhiker with aquarium objects from South America, or perhaps a rare and widespread introduction that has been captured and amplified in the aquarium seawater systems that draw from Yaquina Bay.