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Delaware Canal State Park

The American Shad – Alosa sapidissima

The American shad is the largest member of the herring family. Spawning adults commonly reach four to eight pounds.

Female shad are called “roes” and males “bucks.”

An anadromous species, shad are born in freshwater, spend three to six years at sea and return to their natal waters to spawn.

Adult shad do not eat on their way to spawning grounds. Unlike salmon, not all shad die after spawning and will eat on their return trip to the sea.

For centuries, there has been a dynamic interaction between the Delaware River and the people and cultures that have lived and worked in its basin. One of the best examples of this interaction is the story of the American shad. Because of its predictable migrations, the shad has served as an important resource to many cultures throughout history.

The Lenni Lenape depended on shad as a staple of their diet. They began the traditional methods of preparing shad, by grilling them on wooden racks. The Lenape also preserved shad by air drying and smoking. The shad was an important part of life for the early Moravians and other settlers in the Delaware Valley.

As human populations grew, pollution from sewage and industrial wastewater increased. By the time of the American Revolution, pollution of the Philadelphia waterfront and various tributaries was a serious problem. By the early twentieth century, key fish populations had all but collapsed due to pollution, habitat destruction, and over-fishing.

Water pollution worsened during World War II. In 1946, the Delaware Estuary experienced a 20-mile zone of zero dissolved oxygen, preventing all migratory fish including the American shad from passing into their native spawning grounds.

In 1961, the Delaware River Basin Commission launched a pollution control effort which greatly improved water quality. Unfortunately, pollution was not the only thing effecting the American shad.

During the great canal building era of the 1830s rivers were dammed to ensure water supplies for the canals. Two dams vital to the Delaware and Lehigh Canal system disrupted the shad migration up the Lehigh River preventing the fish from reaching their spawning grounds.

To help the shad re-establish their native spawning grounds on the Lehigh River, while keeping the historic canal intact, park staff have maintained two fish passageways since 1993. These “ladders” allow the fish to navigate upstream, through a series of chambers, around the dams and on to spawning grounds at the Lehigh River as far north as the Frances Walter Dam.


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