2011 Japanese Tsunami Marine Debris (JTMD) Projects

Project Leader

Dr. Henry Choong, Curator of Invertebrates

Research interests

Hydrozoan taxonomy and systematics, NE pacific, anthropogenic debris, population connectivity, transoceanic dispersal

Project overview

The widespread geographic distribution of many marine invertebrate species is often attributed to long-range dispersal, or “rafting.” Rapid, large-scale movement of suitable substrates (surfaces that marine invertebrates can live on) fundamentally changes the dispersal range and limitations for many marine species, particularly those with short pelagic (swimming or drifting) larval stages. The massive tsunami that followed the 2011 earthquake off eastern Japan was an extraordinary transoceanic biological rafting event with no known historical precedent. Entire living communities of coastal marine species on floating derelict docks, boats and other debris travelled across the Pacific Ocean from northern Japan to the west coast of North America.

The Japanese Tsunami Marine Debris (JTMD) projects at the Royal BC Museum are collaborative research efforts involving curator of invertebrate zoology Henry Choong and other research scientists in Canada and the United States, including marine invertebrate systematists, molecular geneticists, biogeographers, and ecologists.

Project activities

These projects are primarily focused on the study of hydrozoans (gelatinous and mostly marine animals related to corals and jellyfish) from the JTMD biological collection, permanently held at the Royal BC Museum in a collaborative agreement with the North Pacific Marine Science Organization (PICES). In 2016, PICES, acting as administrator of a project titled Japanese Tsunami Marine Debris (JTMD): Preservation and Custodianship of an Extraordinary Archive of Biological Samples, awarded a grant to the Royal BC Museum and Henry Choong to archive and curate the unique biological sample collection of biota (marine invertebrates).                                                      

External collaborators include Dale R. Calder, curator emeritus of invertebrate zoology at the Royal Ontario Museum and Royal BC Museum research associate; James T. Carlton of the Mystic Seaport Maritime Studies Program at Williams College, Williamstown, Massachusetts; and John W. Chapman of the Department of Fisheries and Wildlife at Oregon State University’s Hatfield Marine Science Center, Newport, Oregon. The initial paper from this research effort was published in 2013, in the journal BioInvasions Record. In this paper, the authors reported the first transoceanic dispersal record of the western Pacific hydroid Sertularella mutsuensis Stechow, 1931, and discussed the taxonomic and ecological implications of this occurrence. Subsequent papers reported upon collections of additional coastal hydroid species (and one likely pelagic hydroid, Obelia griffini Calkins, 1899). To date, 28 species of hydroids are known from Japanese tsunami marine debris. Overall, researchers have documented 289 living Japanese coastal marine species from 16 phyla (major groups) transported over 6 years on

JTMD objects that traveled thousands of kilometers across the Pacific Ocean to the shores of North America and Hawai‘i.


Selected publications by Dr. Henry Choong
Article Authors
Hydroids (Cnidaria: Hydrozoa) from Japanese Tsunami Marine Debris Washing Ashore in the Northwestern United States.” Aquatic Invasions 9 (2014): 425–440. Calder, D.R., H.H.C. Choong, J.T. Carlton, J.W. Chapman, J.A. Miller and J. Geller.
Sertularella mutsuensis Stechow, 1931 (Cnidaria: Hydrozoa: Sertulariidae) from Japanese tsunami debris: Systematics and Evidence for Transoceanic Dispersal.” BioInvasions Records 2 (2013): 33–38. Choong, H.H.C. and D.R. Calder.
Hydroids (Cnidaria:Hydrozoa: Leptothecata and Limnomedusae) on 2011 Japanese Tsunami Marine Debris Landing in North America and Hawai‘i, with Revisory Notes on Hydrodendron Hincks, 1874 and a diagnosis of Plumaleciidae, new family.” In “Transoceanic Dispersal of Marine Life from Japan to North America and the Hawaiian Islands as Result of the Japanese Earthquake and Tsunami of 2011,” special issue, Aquatic Invasions 13 (2018): 43–70. Choong, H.H.C., D.R. Calder, J.W. Chapman, J.A. Miller, J.B. Geller, and J.T. Carlton.


Get in Touch

Dr. Henry Choong
Curator, Invertebrate Zoology