American Shad Harvest

American shad once supported the most valuable finfish fishery in the Chesapeake. But alosine stocks in the Bay and along the Atlantic coast are now low compared to historic levels, no longer supporting commercial fisheries. The decline of shad has been attributed to overfishing, poor water quality and habitat loss due to dams and other impediments that block spawning migrations.

Overharvesting

Since colonial times, American shad have been valued for their delicious meat and roe. Early written accounts highlighted a tremendous abundance of shad each spring, when the fish migrate from the ocean to their natal freshwater tributaries to spawn.

American shad was one of the first important fisheries in the 19th century. Large crews used huge haul seines to capture spawning shad in Bay tributaries. From 1831 to 1850, fishermen caught 41,000 metric tons of shad annually.

A post-Civil War increase in demand for fish caused shad and other important fisheries (such as oysters) to become severely depleted. By the end of the 19th century:

• Fishermen were catching 8,000 metric tons of shad each year, several-fold less than 50 years before.
• The shad fishery had moved into the lower sections of tributaries and into the Bay mainstem, because historic shad spawning areas had been blocked by dams. Haul seines a mile long were common, and pound and gill nets became increasingly common as well.

Shad landings continued to decline throughout the 20th century. By the 1970s, just 1,000 metric tons of shad were caught each year. In 1980, the Maryland commercial shad fishery closed; Virginia followed suit in 1994. The commercial fishery for American shad continues to be closed Bay-wide.

Dams and Blockages

Physical structures that block or impede spawning migrations have played an important role in the decline of shad and other anadromous fish populations in the Bay. Historically, most alosids spawned in areas now upriver of dams, road culverts and other structures.

• Throughout the colonial period, streams were altered and impounded and mill dams were periodically constructed.
• During the industrial 19th and 20th centuries, steel and concrete and better technology allowed the construction of larger dams in downstream reaches of major tributaries. These blockages eliminated access to important spawning habitats, including all shad runs in the Susquehanna watershed in Pennsylvania.
• By 1940, thousands of dams and small impoundments in the Bay watershed eliminated access to thousands of miles of rivers and streams that shad once used as spawning and nursery areas.
• Acidic mine drainage in some streams also acts as a “blockage” that impedes spawning migrations due to poor water quality.