SEATTLE - Scientists are baffled as to how a group of small
fish native to Japan survived a journey across the Pacific after
they were found on a boat swept away by the 2011 tsunami and washed
up last month on the coast of Washington state.
The batch of striped beak fish - five in all - were discovered
submerged in the hold of the 20-foot-long fishing skiff, dubbed the
Sai-shou-maru, on Long Beach in southwestern Washington.
The vessel, found beached right-side-up, was confirmed this week to
have originated from the region of northern Japan devastated in the
immense tidal surge generated by the March 2011 Fukushima
earthquake.
Other boats carried away by the tsunami have previously washed up
along the U.S. Pacific Northwest and Alaska, as have chunks of
piers and large quantities of other debris. But the fish found
aboard the Sai-shou-maru are the first vertebrates - animals with
backbones - known to have made the voyage.
Marine biologists studying the phenomenon are puzzled over
precisely how striped beak fish, natural denizens of warmer,
shallow southern Japanese waters, ended up as live stowaways in the
well of the boat, and how they endured a two-year journey across
the ocean.
"It is quite remarkable," Curt Hart, a spokesman for the Washington
state Department of Ecology, told Reuters. "Everyone is very amazed
that these fish survived for two years in that hold."
The fish were apparently swept up with the skiff as it was washed
down the coast of Japan and out into the Pacific.
Scientists surmise that the fish made their home beneath the boat
for much of the trip as it drifted upside down and partially
submerged, feeding on other organisms that became encrusted or
otherwise attached to the inverted vessel. Then they might have
been scooped up into the skiff's hold when wind or waves righted
the vessel, Hart said.
NOURISHMENT MYSTERY
The middle of the Pacific is far less rich in nutrients than
coastal waters, raising questions of how the fish found enough food
to survive the trip, said Jeff Adams, an expert at Washington Sea
Grant, an agency supporting marine research.
The 6-inch-long striped beak fish, named for their protruding
mouths and black-and-white striped markings, were the most
surprising of an estimated 30 to 50 species of marine organisms
that hitchhiked across the Pacific with the skiff.
Other stowaways included various types of algae, anemones, crabs,
marine worms and shellfish.
Many were believed to be non-native species, and all were treated
as potentially invasive - capable of displacing native organisms
and disrupting the natural ecological balance if allowed to escape
into the environment and propagate.
As a precaution, state officials swiftly removed the Sai-shou-maru
from the shoreline before samples of organisms were collected for
study, and the boat was scraped and steam-cleaned, Hart said.
Four of the fish found alive in the boat on March 22 have since
died, and the lone surviving specimen has been moved to an aquarium
in Seaside, Oregon.
The Sai-shou-maru is not the only Noah's ark of potential invasive
species carried to the U.S. West Coast by the tsunami. Several more
Japanese boats have washed ashore since last year in Washington,
Oregon and California, and a fishing vessel found drifting off
Alaska was scuttled by the Coast Guard.
Dozens of non-native and potentially invasive species - more than
hitched a ride aboard the Sai-shou-maru - were previously found
attached to two large hunks of piers that washed up, one in Oregon
and one in Washington, Hart said.