AUGUSTA (AP) — Jason Moak, senior research scientist for the Southeastern Natural Sciences Academy, and other scientists are monitoring the annual shortnose sturgeon migration in the Savannah River.

About 20 of the endangered fish were fitted with tiny radios as part of an effort to learn more about their spawning habits.

Moak says trying to track them is not easy.

In the Savannah and many Eastern rivers, the creation of dams and lakes has eliminated most of the sturgeon’s ancestral spawning areas. Scientists want to know whether the few suitable spawning areas left are sufficient to sustain the imperiled species.

Moak uses listening stations scattered among 200 miles of river in efforts to find the tagged fish.

Although a tagged, egg-laden female spent six days below Augusta’s New Savannah Bluff Lock & Dam in April 2009, none has been detected that far inland this year.