Four years back, Japan witnessed tsunami after an earthquake having magnitude of 9.0. Till now, debris from the incident continues to wash ashore in Washington State. More concerning is it is bringing along many unwelcoming visitors.

As per Japanese officials, tsunami may have led up to five million tons of debris, including refrigerators, tires and even entire boats, into the Pacific. The debris is being passed on to the American shores. The debris is not the only problem, as it has been found that it is being colonized by dozens of invasive species and parasites.

Allen Pleus of the Department of Fish and Wildlife's aquatic and invasive species unit said, “These become their own ecosystems in the ocean. What's not natural is that they're on man-made objects that don't disintegrate”.

Lately, a 25-foot Japanese skiff, has been discovered along the rocky shores near La Push. This year, it is the third object to reach Washington shores. Since the tsunami incident has taken place, around 40 such objects have reached the shore.

Experts said that the debris is teaming up with invasive species, which was able to survive the long journey. It is not surviving, but actually thriving when experts found them.

These invasive species are quite harmful and can cause great damage to ecosystems. Invasive species compete with native species and in certain cases, they can even interrupt food chains, deplete resources and even wipe off entire species.