OREGON STATE UNIVERSITY

You are here

Japanese Tsunami Marine Debris

On March 11, 2011 a magnitude 9.0 megathrust earthquake struck the coast of Japan, resulting in a wave of aftershocks and devastating tsunami. An estimated 5 million tons of debris was swept into the ocean.

On March 11, 2011 a magnitude 9.0 megathrust earthquake struck the coast of Japan, resulting in a wave of aftershocks and devastating tsunami.  An estimated 5 million tons of debris was swept into the ocean.  Most tsunami debris sank; but 1.5 million tons is estimated to be floating on the Pacific Ocean.  Some tsunami debris has found its way to shores on the Eastern Pacific; much more is circulating in the N. Pacific Gyre. Debris will continue to wash onto shore for years based on ocean currents and circulation.

Floating debris is often a mini ecosystem of sea stars, algae, hydroids, barnacles, bivalves and sometimes fish. Many organisms are washing ashore alive and attached to tsunami debris.  Biologists can use these organisms to confirm date and origin of tsunami debris.  Biologists are concerned that species landing ashore could become invasive once established.

The cultural and biological consequences of the Tohoku quake and tsunami will last for decades. Communities struck by the tsunami are still not fully recovered.  Floating marine debris and their attached foreign organisms have broad biological consequences.  Your reporting of tsunami debris and foreign organisms is very important!

  • Does tsunami debris you found on the beach have marine organisms?  Contact OregonBeachcomber/HMSC Marine Bioinavsion Lab at http://tinyurl.com/reportdebris

The symbol above is Maru meaning 'circle' or 'whole'.  It is often used in naming commercial and recreational boats. Most of the boats that have washed ashore in Oregon include this character in their names.