COMMUNITY
November 5, 2018
THE ASIAN REPORTER n Page 9
Algae from Japanese tsunami debris has not taken a foothold in Oregon
By Mark Floyd
Special to The Asian Reporter
EWPORT, Ore. — Researchers
from the United States and Japan
have identified 84 species of
marine algae and cyanobacteria that
arrived on the Pacific Northwest coast via
debris from the 2011 Tohoku earthquake
and tsunami and, to date, none have
gained a foothold in U.S. coastal waters.
Since more than a dozen of the algal
species are on a global list of dangerous
invasive organisms, Oregon and Washing-
ton may have dodged the proverbial bullet,
experts say. It will take several more years
to be certain none of the species that were
aboard the debris have become estab-
lished, but the outlook appears to be good.
Results of the algal research were
published in the journal Phycologia.
Lead author Gayle Hansen, an Oregon
State University algal taxonomist, said
more than 80 percent of the algae were
fertile when they arrived. However, quick
action by the Oregon Department of Fish
and Wildlife (ODFW) appears to have
prevented most of the species from
colonizing the shore.
“When the large concrete dock laden
with marine algae and invertebrates
washed ashore near Newport, Oregon,
some 15 months after the tsunami, I was in
the parking lot [with] ODFW folks
discussing the fouling Japanese biota …”
Hansen said. “They decided it was
imperative to remove not only the dock,
but also all future tsunami debris that
washed ashore on Oregon beaches as soon
as possible after landing in order to reduce
any possible species invasion.
“That turned out to be an extremely wise
decision. When the debris materials were
removed from the beaches, so was the risk
of most of the algal-fouling species colon-
izing our shore. Although a large number
of the algae were in a reproductive state,
their spores typically don’t live for very
long, or disperse very far, so getting them
off the beaches quickly was a smart move.”
The 9.0 magnitude earthquake gener-
ated tsunami waves that were more than
30 feet high in the open ocean, and
eventually reached more than 125 feet in
some areas as the water surged inland.
The tsunami carried as far as six miles
N
inland and the Japanese Ministry of the
Environment estimated that 4-5 million
tons of debris from the disaster washed out
to sea — and about 30 percent was buoyant
enough to float.
Numerous species of algae and bacteria
were attached to debris items that drifted
across the north Pacific Ocean and landed
in Oregon and Washington. Hansen and
her
Japanese
colleagues,
Takeaki
Hanyuda and Hiroshi Kawai of Kobe
University, identified, described, and
began analyzing the distribution of these
species between 2012 and 2016. About 61
percent of the species were thought to
already be in the northeast Pacific before
the tsunami, but a number of them turned
out to vary genetically. In fact, the
haplotype variation in eight of the shared
species was sufficiently different to
consider them to be a new genetic invasion
risk.
The study, which was funded by the
Japanese Ministry of the Environment,
also enabled the researchers to identify a
number of new organisms, which
previously had not been described in the
literature.
Thirteen of the species were on a global
watch list for invasive species and three
were considered particularly hazardous —
Undaria pinnatifida, Codium fragile sub-
species fragile, and Grateloupia turuturu.
Undaria pinnatifida, a brown alga up to
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three to four feet in length on the debris,
was the largest of the species.
“It is considered highly invasive, partly
because it can reproduce up to three times
a year,” Hansen said. “A form of this
species was introduced into California in
2000 and they’ve had trouble eradicating
it. Normally found on docks and in the
shallow subtidal waters, it can edge out
native plants like Nereocystis, the bull
kelp, a keystone species in the nearshore
regions of Oregon and Washington.”
Codium fragile subspecies fragile was
found abundantly coating the surface of a
derelict Japanese boat near Road’s End,
north of Lincoln City, Oregon. “It appeared
as a greenish-black to brown turf that only
occasionally produced the upright,
branched finger-like fronds typical of this
species,” Hansen noted. “It is quite
invasive and reproduces asexually, which
means it can reproduce very easily, at any
time. That one was a big scare.”
A third dangerous species to arrive on
tsunami debris was Grateloupia turuturu,
a species that has been a major problem on
the east coast, especially in New England
bays, where it crowds out native seaweeds.
It is also listed among the 100 worst
invaders in the Mediterranean Sea. The
turuturu form found on debris in the
Pacific Northwest was genetically slightly
different than the New England form, so it
may not be as highly invasive, Hansen
ALARMING ALGAE. Researchers from the
United States and Japan have identified 84 species
of marine algae and cyanobacteria that arrived on
the Pacific Northwest coast via debris from the 2011
Tohoku earthquake and tsunami and, to date, none
have gained a foothold in U.S. coastal waters. A con-
crete dock (left photo) at Agate Beach had 31 differ-
ent algal species and a boat (right photo) near Seal
Rock, Oregon, had 20. (Photos courtesy of Oregon
State University)
said.
The concrete dock at Agate Beach, which
was the largest debris item, had 31 differ-
ent algal species — the most found on any
debris item during the study. However,
other items also carried numerous algal
species. A boat at Horsfall Beach in
southern Oregon bore 25 different species,
the Road’s End boat near Lincoln City had
24, and a boat near Seal Rock, Oregon, had
20. Algae species were also found on pipes,
tanks, pallets, baskets, beams, a tire, and
even a plastic carboy.
“The State of Oregon was able to remove
about 90 percent of the derelict and
damaged vessels from Japan that arrived
along Oregon beaches — and most of the
vessels were immediately removed from
the surf zone over a period of 24 hours or
less,” said Steven Rumrill of ODFW.
Volunteer groups including SOLVE and
Surfriders then quickly removed most of
the smaller debris items and their biota.
“The cleanup efforts were so efficient that
it was often difficult to get material to
study for our assessment of the invasion
threat,” Hansen said.
Washington had a similar response and
success rate, according to Allen Pleus of
the Washington Department of Fish &
Wildlife.
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