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Eyeing Gulf Coast walleye through genetics

5/31/2006
The Gulf Coast walleye is genetically different than ordinary walleye found throughout the country. 

On the surface, they look like most any walleye. They've got the
faraway eyes, raspy scales, and the jaw of an adept, toothy predator. But
the Gulf Coast walleye is different. And that difference and their decline
has the attention of biologists at the U.S. Fish & Wildlife Service's Pvt.
John Allen National Fish Hatchery (NFH) and Mississippi State University
(MSU).

Over most of its range, the walleye is a fish synonymous with cold
winters and cool waters, and a fish that takes to flat water to live most
of its life. It takes so well to lakes, that it's often stocked in
reservoirs to provide great angling and among the finest of table fare.
But the Gulf Coast walleye is not your everyday northern walleye, and the
difference is coiled up in its DNA.

The only surefire way to tell a Gulf Coast walleye apart from its
next of kin to the north is through genetics. And that difference in
genetics is an expression of how long the southern variety has been
separated from fish to the north and adapted to a southern clime. Those
genetic differences underscore what biologists already know about the
fish's biology, behavior, and how it makes a living.

The Gulf Coast walleye's DNA holds the code for survival after eons
of separation from its more northern neighbors. Gulf Coast walleye is
essentially a cool-water fish fit to survive in warm southern rivers; it's
only found in nature in the Tombigbee River and Coosa River systems.
They're adapted to river life in the South, a climate that would readily
kill a northern-strain walleye.

Pvt. John Allen NFH, located in Tupelo, Miss., holds and intensively
manages a brood stock; it's a refuge — the only captive population that
exists. MSU and the hatchery are studying habitat use in the wild,
collecting future brood stock, and exploring captive-fish diets to get more
advanced fish to face the rigors of the wild after stocking.