Gray
Whales and Tsunamis
by Dr. David Rugh
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Dr.
David Rugh
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"With
the tsunami, are the whales okay?" This
question came to Journey north from a 4th grader. We asked gray whale expert
Dr. David Rugh for his thoughts:
Possible Impact
"Without documentation, I'm left to speculate, and perhaps anyone else
who thinks about the affect of a tsunami on whales can only speculate
too. My first thought is that whales will be almost unaffected. At
sea they will have the sensation of a wave passing when the tsunami
goes by,
much as vessels at sea do, without any deleterious affect. The place
where there might be a problem would be near shore when a tsunami rapidly
pulls water out to sea before a wave hits the shore. Whales might be
stranded for a moment and then pushed hard against tidal rocks as the
tsunami overwhelms them. Therefore, the degree of impact may be a function
of proximity
to the coast. In the days following a tsunami, there might be an increase
in strandings of marine mammals if the wave was deadly. Otherwise,
most marine mammals will probably go about their business unaffected.
More About Tsunamis
"Tsunamis have different sizes and dynamics, so they will not be consistent
in how they impact the environment. Sometimes a tsunami is first evident
by
a large draw-down of water followed by a series of huge waves; sometimes
there is no draw-down at all — that is, almost no warning. The
topography of coastal areas makes a big difference as to how these waves
behave near
shore. This inconsistency makes it harder to generalize about impact.
Videos of tsunamis sometimes show a beach becoming exposed for a short
while, and then a high wave comes in. If a whale was very near the beach
at that moment, it might be pulled out to sea or — for a few tens
of seconds — it might be stranded. It's the force of the incoming
wave that could be especially hard on living things. What I imagine could
be done for
documenting what a tsunami does to whales is to maintain beach watches,
recording dead cetaceans — not a very sophisticated plan, but at
least that record could indicate increased deaths following a tsunami."
A
Complex Process
It is unfortunate that the only way to get documentation would mean
more
tsunamis and so many other things that we don't plan ahead for
or think
about. But study and documentation are necessary before conclusions can
be made. Study and documentation take time. Sometimes we turn up new
information that changes "old" answers. We are always learning!
Journal or Discussion Questions:
- We always
expect scientists to know all the answers. But answers have to come
from someplace. What is one question for which you've never received
an answer that satisfies you? Do you think there is just one answer
to your particular question? Explain.
- When
an event like this occurs, how does it remind us that ALL living
things are connected?
How are the impacts of natural disasters or weather events felt around
the world in these modern times?
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