STURGEON 'SONG' MAY HELP SOLVE MYSTERY OF DISAPPEARING
FISH
AUBURN -- "Wheee uck . . . wheee uck . . . wheee uck."
(http://www.ag.auburn.edu/faa/ichthyology/sound.html )
That's the song of the pallid sturgeon -- a fish that's a distant cousin of the
beluga sturgeon, famous as the source of Russian caviar, and a close
cousin of the Alabama sturgeon.
Although it's not audible to the human ear, this "sturgeon song" can be
heard with special underwater microphones and may one day enable
researchers to locate the dwindling populations of Alabama sturgeon.
Prehistoric survivors of the ice age, sturgeon are among the world's most
imperiled species. In Alabama, they are declining in part due to
construction of dams that limit spawning migration and reduce habitat for
juveniles.
The Alabama sturgeon was once found in the Cahaba and the
Tombigbee rivers, but now they are located only in the Alabama River. At
least that?s what state biologists think. Carol Johnston, a biologist with
the Auburn University Peaks of Excellence research initiative in the
Department of Fisheries and Allied Aquacultures, is working with the state
to solve the mystery of the disappearing sturgeon.
Johnston specializes in the conservation and ecology of freshwater
non-game fishes and works with acoustic signals to monitor populations.
Acoustic signals are used for monitoring population of many animals,
including birds, frogs, bats, insects, whales and fishes. Animals produce
signals during the breeding season to attract a mate or to defend their
territory. Once researchers can describe a signal of a certain species,
they can listen for the signal in the field and use it to locate and monitor
the population of that species.
"The most basic kind of information we can get from acoustic signals is
where the sturgeon are," says Johnston. "Then maybe we can figure out
how many are there and what species are there. If we know where they
are, it helps us understand habitat use, and also fish may be captured for
captive breeding and other studies.
"This is really important for the Alabama sturgeon because they are
almost gone. They are in such low numbers that we can't find them
anymore. The state biologists think that there are less than 100 in the
wild, so we need any clue we can get to find them."
Researchers have gathered a few clues so far.
They discovered that pallid sturgeon and shovelnose sturgeon produce
sounds during the breeding season. Next, they plan to locate a breeding
population and confirm that these sounds can be recorded in the wild.
And finally they will go to places where Alabama sturgeon populations are
thought to exist and listen for the sounds. They hope to locate populations
of sturgeons in Alabama rivers, including the Alabama sturgeon.
Why is conservation of this dwindling population of sturgeon important?"
"Conservation is important on a number of levels," says Johnston. "The
first one is ethical. It's not our place to purposefully eliminate things from
the earth.
"The more functional reason is that when we start losing species, the
ecosystem just doesn't work the same way. And we can't predict how it?s
going to function; it could have consequences that we can?t repair."
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