Sertularella mutsuensis Stechow, 1931 (Cnidaria: Hydrozoa: Sertulariidae) from Japanese tsunami debris: systematics and evidence for transoceanic dispersal

Henry Choong,Dale Calder

doi:10.3391/bir.2013.2.1.05

Abstract

The leptothecate hydroid Sertularella mutsuensis Stechow, 1931 is reported on debris from the 2011 Japanese tsunami that came ashore on 5 June 2012 at Agate Beach north of Newport, Oregon. Its discovery on a barnacle (Semibalanus cariosus) from a derelict floating dock originating at Misawa, Honshu, confirms the capability of successful transoceanic dispersal for this species. We compare our specimens to Stechow’s syntype material of S. mutsuensis in collections at the Zoologische Staatssammlung Munchen, and designate a lectotype and paralectotype of the species.

Highlights

The catastrophic Tôhoku earthquake and tsunami of 11 March 2011 resulted in floating debris extending thousands of kilometers to the north of Hawai’i in the Pacific Ocean, some of which has appeared on the west coast of the United States (NOAA 2012)
We report the first transoceanic dispersal record of the western Pacific hydroid Sertularella mutsuensis Stechow, 1931, collected from the Misawa floating dock, and discuss the taxonomic and ecological implications of this occurrence
Colony fragments of the hydroid Sertularella mutsuensis reported were found attached to a barnacle Semibalanus cariosus (Pallas, 1788) collected from the Japanese dock that stranded on Agate Beach, Oregon, on June 5, 2012

Summary

Introduction

The catastrophic Tôhoku earthquake and tsunami of 11 March 2011 resulted in floating debris extending thousands of kilometers to the north of Hawai’i in the Pacific Ocean, some of which has appeared on the west coast of the United States (NOAA 2012). A188-ton dock originating from Misawa, Honshu, Japan, came ashore on 5 June 2012 at Agate Beach, 4.7 kilometers north of Newport, Lincoln County, Oregon (ANS 2012). The derelict dock carried with it a substantial fouling assemblage, including over 100 nonnative species We report the first transoceanic dispersal record of the western Pacific hydroid Sertularella mutsuensis Stechow, 1931, collected from the Misawa floating dock, and discuss the taxonomic and ecological implications of this occurrence. Sertularella mutsuensis was first described from Suzu-uti Mura, near Asamushi, Mutsu Bay, Japan, and has not been reported from North American waters

Materials and methods

Discussion