03/25/2002

Sturgeon Song May Help Solve Mystery of Disappearing Fish

AUBURN, Ala. – Did you know that sturgeon sing?

"...wheee uck, ... wheee uck, ...wheee uck." This is the song of the pallid sturgeon–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, which limits spawning migration and reduces habitat for juveniles.

The Alabama sturgeon used to be 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. To solve this mystery of the disappearing sturgeon, they called in Carol Johnston, a biologist with the Auburn University Peaks of Excellence research initiative in the Department of Fisheries and Allied Aquacultures. 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.

According to Johnston, "The most basic kind of information we can get from acoustic signals is where the sturgeon are. 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? Johnston says, "Conservation is important on a number of levels. 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."

(If you want to listen to a recording of the pallid sturgeon, visit this web site: http://www.ag.auburn.edu/faa/ichthyology/sound.html)

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News from:

Office of Ag Communications & Marketing

Auburn University College of Agriculture
Alabama Agricultural Experiment Station
3 Comer Hall, Auburn University
Auburn, AL 36849
334-844-4877 (PHONE) 334-844-5892 (FAX)

Contact Jamie Creamer, 334-844-2783 or jcreamer@auburn.edu
Contact Leigh Hinton, 334-844-5887 or hintola@auburn.edu

March 2002