Effects of the Fukushima nuclear disaster on animals will be bad, but how b ad?

From ANIMAL PEOPLE, April 2011:

FUKUSHIMA–Humans were evacuated from
within a 20-kilometre radius of the
earthquake-damaged Fukushima nuclear reactor
complex soon after the overheated reactors and
spent fuel ponds began leaking radiation. Most
who left homes that escaped destruction from the
ensuing tsunami are believed to have taken their
pets–but wildlife, farm animals, and pets left
amid the rubble of shattered seaside communities
remained exposed.

What may become of animals downwind of
the Fukushima reactors will ultimately depend on
the yet-to-be-determined severity of the
incident. What was known, as ANIMAL PEOPLE went
to press, was only that nuclear experts rated
Fukushima somewhere in seriousness between the
near-meltdown in Three Mile Island in 1979 and
the meltdown at Chernobyl, Ukraine, in 1986,
with potential to exceed Chernobyl in the
worst-case scenario of a triple meltdown.
The Three Mile Island and Chernobyl
incidents both occurred in rural areas, with
relatively little effect on pets. While the
radioactive plume from Fukushima has mostly blown
out to sea, any that drifts over nearby land
will be exposing pets as well as humans in
densely populated cities, from Sendai to Tokyo.
The largest body of research pertaining
to the effects of nuclear radiation on dogs was
produced by Leo K. Bustad, 1920-1998, better
remembered for establishing the National Service
Dog Center during his 15 years as president of
the Delta Society. Bustad from 1948 until 1965
did invasive radiation research on animals at the
Hanford National Laboratory in Washington state,
trying to project the outcomes from using nuclear
weapons. He continued his studies from mid-1965
to 1973 as head of the radiobiology and
comparative oncology labs at the University of
California in Davis. The radioactive remains of
1,200 beagles used in his experiments were stored
at an off-campus location which became a
top-priority Superfund toxic waste cleanup site.
The experiments that Bustad began ended
in 1986, when the last beagle died. The dogs’
remains were removed to Hanford in 1990. Most of
the research merely confirmed that what was
already known or suspected about the effects of
nuclear radiation on humans also pertains to
dogs, and probably to any mammal.
The major sources of information about
effects of radiation on wildlife are ongoing
studies in the Chernobyl region–where scientific
perspectives have nearly reversed during the past
five years.
Research published in April 2006
indicated, as Stephen Mulvey reported for BBC
News, that “The exclusion zone around the
Chernobyl nuclear power station is teeming with
life. As humans were evacuated from the area 20
years ago, animals moved in. Existing
populations multiplied and species not seen for
decades, such as the lynx and eagle owl, began
to return. There are even tantalising footprints
of a bear,” Mulvey noted, “an animal that has
not trodden this part of Ukraine for centuries.”
Said radioecologist Sergey Gaschak, “A
lot of birds are nesting inside the sarcophagus,”
the steel and concrete shield built to contain
the reactor.”
“There may be plutonium in the zone,”
wrote Mulvey, “but there is no herbicide or
pesticide, no industry, no traffic, and
marshlands are no longer drained. There is
nothing to disturb the wild boar–said to have
multiplied eightfold between 1986 and
1988–except its similarly resurgent predator,
the wolf.”
In 2007, however, Anders Moller of the
Université Pierre et Marie Curie in France and
Tim Mousseau of the University of South Carolina,
found in a more exhaustive study that, “Species
richness, abundance and population density of
breeding birds decreased with increasing levels
of radiation.”
Counting 1,570 birds from 57 species,
Moller and Mousseau found that the number of
birds in the most contaminated areas was only a
third of the population found at sites with
normal background radiation levels. The number
of bird species found in the most contaminated
areas fell by half.
A follow-up study reported in August 2010
that radioactive contamination appeared to most
harm brightly colored birds and birds who migrate
from far places.
“One explanation may be that these
species have, for whatever reason, less capable
DNA repair mechanisms,” Mousseau told BBC News
science reporter Victoria Gill.