Dredge barge plus inset darter

Dredge barge plus inset darter

Gravel dredging barge

Immense barges bearing huge shovels have scooped gravel out the Allegheny's pools 7 and 8 for decades. In gauging the impact of the substratum removal on the river's aquatic life, researcher Jonathan Freedman studied small fish, such as the rainbow darter shown in the inset, because they have limited movements and specific habitat requirements, making them more susceptible to the effects of dredging.

Image: Courtesy Jonathan Freedman