Taxonomy of <i>Caprella</i> (Crustacea: Amphipoda: Caprellidae) recovered from a large fisheries dock stranded in Oregon, USA that had been carried away by the 2011 East Japan Earthquake and Tsunami

The 11 March 2011 Great East Japan Earthquake generated a massive tsunami that triggered an extraordinary release of floating transoceanic marine debris. That floating debris subsequently landed on coastlines from Midway Atoll to the Hawaiʻian Islands and from south central Alaska to central California of North America. Two species of Caprella (Crustacea: Amphipoda: Caprellidae) were collected from a large concrete fisheries dock (approximately 20 m length) that was part of the floating debris, on Agate Beach, near Newport, Oregon, USA, on 5 June 2012. The caprellids recovered from the dock are identified as Caprella cristibrachium Mayer, 1903 and C. mutica Schurin, 1935. Caprella cristibrachium had not been observed previously outside of the Bering Sea to the Far East Asia. The robust body somites and short antennae and basis of gnathopod 2 make C. cristibrachium suitable for attaching the filamentous macroalgae and/or marine invertebrates on the large tsunami fishing dock. Caprella mutica, originally recorded from the Far East Asia, was previously introduced to Oregon, to other cold-water areas between northern California and Alaska, the eastern and western North Atlantic and to the southern hemisphere.