Japanese Tsunami Brings Invasive Species To West Coast

Elaine Radford

Japanese tsunami debris is still arriving on the shores of North America's west coast, and it's contaminated with at least 175 living species, about half of which have been identified. That's why scientists are becoming concerned about the possibility of an invasive species entering the continent, according to a report today in Nature by Virginia Gewin.

The federal National Oceanic and Atmospheric Administration (NOAA) said that the debris is the result of the March 11, 2011 earthquake and tsunami that struck Japan with devastating power, killing almost 16,000 people and causing almost unbelievable destruction. The powerful wave swept a great deal of debris into the sea where it is expected to continue traveling on ocean currents for several years.

The debris is not radioactive, but, if you encounter any, you should report it to NOAA by emailing DisasterDebris@noaa.gov. Some of the pieces represent a public danger just because of their size. For instance, Nathan Francis reported on a 185 ton section of a Japanese dock that washed up on the shore of Olympic National Park in Washington State in late December. It will ultimately cost $628,000 to remove the huge structure including a $478,000 contribution for cleaning up tsunami debris from Japan.

While the cost of the debris removal is certainly a concern, what startled the marine biologists was the fact that living creatures could actually survive the rough ride. According to Nature, no one predicted that coastal Japanese species could survive a trip across an estimated 8,000 kilometers of open water before slamming into land.

Jessica Miller, a marine ecologist at Oregon State University, studied another section of dock which traveled from Misawa, Japan to the central Oregon coast. The 165 ton block of concrete held "tens of thousands of organisms in layers up to 15 centimetres thick, including brown algae, pink barnacles and shrimp-like creatures called caprellids."

Now, it has been proven that these floating concrete islands can carry potentially invasive species including three well-known invasive algaes. Gayle Hansen, an algae expert for Oregon State University, has examined 46 species from the debris, and she said that three-fourths of them were active and capable of dropping spores. In other words, they can grow, reproduce, and spread even after their long journey.

Fortunately, there is no evidence yet that any invasive species has actually escaped from the Japanese tsunami debris. But biologists are keeping a wary eye on the situation.