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A Shad Situation

The population of American shad rebounded in the 1990s but is again on the wane.

Shad at the Cnowingo Dam on the Susquehanna River in Maryland.Bob A. Sadzinski

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This month American shad conclude their long journey from oceans to river spawning grounds. Or so conservationists hope. A four-year assessment concluded in 2007 that this iconic Atlantic Coast native was at its lowest abundance ever, and the decline continued last year.

Shad have faced threats before. Over­fishing, pollution, and the blocking of spawning grounds by dams once devastated their populations. Then, in the early 1990s, cleaner rivers, fish ladders, and fry from hatcheries spurred a recovery that looked promising. But biologists monitoring shad with electrofishing surveys (using an electric current to briefly stun fish so they can be counted) and fish-passage tallies report that the species has been on the wane again in recent years.

“Shad are continuing a downward trend that began around 2000,” says Michael Hendricks, a fisheries biologist who leads the Anadromous Fish Restoration Unit at the Pennsylvania Fish and Boat Commission. Offshore fishing for herring, ...

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