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Toadfish
The
oyster toadfish is a year-round resident of the Chesapeake
Bay. Although the 69 other members of its family of Batrachoididae
also live in the waters of the western Atlantic from Maine
to the West Indies, Opsanus tau, the oyster toadfish,
is the only toadfish species in the Chesapeake Bay.
Also
known as the oyster cracker, the oyster toadfish preys
on crustaceans, mollusks, fish, and just about anything
else it can find.
Despite
its rather ugly appearance, the toadfish has peaked the
interest of many people, especially medical researchers.
By studying the fish, the researchers hope to learn a
lot about the human body.
What's
so amazing about this fish?
To
start with, the swim bladder of the oyster toadfish is
quite a work of art. To create a grunting noise—similar
to a foghorn—that males use to attract females, the
toadfish vibrates its swim bladder 200 times per second.
Compare this to the next fastest muscle in the vertebrate
world, the muscle in a rattlesnake's tail, which moves
at a mere 90 Hertz (vibrations per second), or to the
wings of a hummingbird, which "only" beat 50
to 60 times per second, and you know that 200 times per
second is fast. Very fast.
By
studying the unique pace of the toadfish swim bladder
and how it's able to so quickly contract and relax, scientists,
such as Larry
Rome
,
a muscle physiologist at the University of Pennsylvania,
hope to get a better understanding of how muscles work.
"Knowing
how a healthy motor system works will make it much easier
to identify the mechanisms for muscle pathologies,"
Rome said in an article
in Lab Notes.
"For instance, some types of heart disease involve
slowing of the relaxation rate of cardiac muscle. Our
research sheds light on the mechanisms that can cause
that slowing. Further, we are using, and thus characterizing,
artificial compounds that may be able to 'rescue' muscles
that are relaxing too slowly."
Another
remarkable feature of the oyster toadfish is its ability
to tolerate high concentrations of ammonia. The fish can
survive ammonia levels 10-20 times higher than humans
can handle. This is interesting for medical researchers
because the onset of disease, especially failure of the
liver, often leads to high ammonia concentrations that
are harmful to the brain.
Scientists
are also using the islet cells of the toadfish, which
include insulin-secreting (beta) cells, to research diabetes.
By studying these cells, researchers learn more about
the basic functions in humans and how these can be affected
during a disease.
In
addition to its important status in the medical world,
this ugly-looking fish from the bottom of the Bay also
has another claim to fame: Toadfish have traveled more
than 3 million miles in space.
Launched
from the Kennedy Space Center in October of 1998, the
toadfish were part of a research project to determine
the effects of micro-gravity on their balance system.
Like
all other vertebrates, a vestibular system of fluid-filled
canals in its ears provide a sense of balance and equilibrium.
Stephen M. Highstein has studied the balance system of
the oyster toadfish for 20 years at the Marine Biological
Lab in Woods Hole, Massachusetts. Studying the toadfish
helps him and other scientists to understand the causes
and effects of motion sickness, dizziness and nausea,
and more serious balance disorders such as Meniere's disease.
References
and further reading
Related
Watershed Radio programs
- Search
for other stories in the Watershed Radio Archive.
There are many more stories about fish
in the Chesapeake Bay watershed.
About
the toadfish
- University
of Pennsylvania Press Release:
Ideal for booming mating calls, certain fish muscles
have evolved so fully that they're unfit for much else.
The University's website also includes Dr.
Lawrence C. Rome research page
and sounds,
movies, and images
of the toadfish.
- Could
Tough Toadfish Be Key to Medical Mystery?.
Article on National Geographic website.
- It's
hard to love a toadfish.
An article in The Collecting Net, Vol. 3 No.
5, August 1985, a publication of the Marine Biological
Laboratory in Woods Hole, Massachusetts.
- It's
Not Going to Win Any Beauty Contests But....
Article in Lab Notes, 97, Vol. 6., No. 3, a publication
by the Marine Biological Laboratory in in Woods Hole,
Massachusetts. The same issue includes On
Balance, Biologists Find A Lot of Reasons to Study Toadfish.
- Toadfish
in Space:
NASA Studies Balance in Two Woods Hole Toadfish, a Senator,
and Six Astronauts on Historic Shuttle Mission. Article
in Lab Notes, Fall 98, a publication by the Marine
Biological Laboratory in Woods Hole, Massachusetts.
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