If we want to see fish along our shorelines, don't divide them from land with walls

Jeff Houghton notices the difference most when he's underwater.

If the research technician for the University of Wisconsin-Milwaukee School of Freshwater Sciences is in water that butts up against natural landscape, the area is teeming with life.

If he's in water separated from land by a corrugated metal or concrete wall known as a bulkhead, there are few fish and the area seems barren.

Now, a study by scientists at Shedd Aquarium in Chicago backs up with data his anecdotal experience with the sharp, man-made divisions between land and water in the Milwaukee harbor and along major sections of the Milwaukee, Menomonee and Kinnickinnic rivers in the city. Though most people may not give them a second thought, scientists have long suspected these structures may pose barriers for animals living along the shore.