American shad form an important link in the Bay food web. Shad feed on plankton and small fishes. In turn, they are preyed upon by larger fish, including bluefish, weakfish and striped bass.
Historically, local economies flourished from the annual shad run in the spring, when the fishes’ upriver migration begins. But shad populations were decimated in the 1970s by overfishing, pollution and dams and other blockages that prevent the fish from spawning in upstream habitats.
Learn more about shad harvest and management.
The goal for American shad is based on an estimate of the spawning shad stock in major river systems, some with fish passage systems in place to bypass existing blockages by dams and other barriers.
- Susquehanna River: Two million shad passing York Haven Dam annually
- James River: 500,000 shad passing Boshers Dam annually
- Potomac River: 31.1 Catch per Unit Effort (CPUE)
- York River: 19.54 CPUE
Long-term trend
N/A -- indicator lacks 10 years worth of data.
Short-term trend (10-year trend)
The short-term trend has been one of slow but steady overall improvement, with considerable variability between the rivers until 2005-2006.
- A sharp decline in shad passed at York Haven Dam (Susquehanna River) occurred in 2007 and 2008.
- The York River shad index has declined from 41.2 percent in 2004 to 24.1 percent in 2008.
- Shad counts at Boshers Dam (James River) indicate a decline, although they are variable.
- Shad have continued to improve in the Potomac River, reaching 75.2 percent of that river’s goal.
The overall trend for Chesapeake Bay shad has slowly increased, largely due to increasing CPUE on the Potomac River coupled with continued poor passage at York Haven Dam and Boshers Dam. Between 2000 and 2008:
- Bay-wide Index: Increased from 9.2 percent to 23.4 percent of goal achieved
- Susquehanna River: Decreased from 0.234 percent to 0.001 percent of goal achieved (from 4,687 shad to 21 shad passing York Haven Dam)
- Potomac River: Increased from 12.4 percent to 75.2 percent of goal achieved (6.4 to 24.1 CPUE)
- York River: Decreased from 36.7 percent to 24.1 percent of goal achieved (8.43 to 6.64 CPUE)
- James River: Increased from 0.003 percent to 0.009 percent of goal achieved (from 16 shad to 43 shad passing Boshers Dam)
Change from previous year (2007-2008)
- Bay-wide Index: Increased from 21.7 percent to 23.4 percent of goal achieved
- Susquehanna River: Decreased from 0.010 percent to 0.001 percent of goal achieved (from 192 shad to 21 shad passing York Haven Dam)
- Potomac River: Increased from 66.7 percent to 75.2 percent of goal achieved (21.7 to 24.1 CPUE)
- York River: Decreased from 27.5 percent to 24.1 percent of goal achieved (7.13 to 6.64 CPUE)
- James River: Decreased from 0.017 percent to 0.009 percent of goal achieved (from 84 shad to 43 shad passing Boshers Dam)
American Shad Restoration Goal
The Chesapeake Bay restoration goal for American shad is an estimate of the spawning shad stock that can be supported with existing riverine blockages. The demographics and population dynamics of such a restored American shad population are unknown and the potential response to harvest has not been explored. Therefore, attainment of the Chesapeake Bay restoration goals is not connected to fisheries management decisions regarding this species.
American shad are a coastal species; therefore, management decisions, such as the harvest moratorium and allowable bycatch, are determined by the Atlantic States Marine Fisheries Commission (ASMFC).
Susquehanna and James River Shad Values
The Susquehanna and James River counts are determined by fish passage data at York Haven and Boshers Dams, respectively.
- Assessment of the Susquehanna River was changed from shad passage at Conowingo Dam to shad passage at York Haven Dam to reflect the goal of two million shad passing the York Haven Dam annually.
- On the James River, American shad passage at Boshers Dam is compared to a passage goal of 500,000 shad.
The Susquehanna River restoration goal of two million American shad above the York Haven Dam was developed for the 1981 FERC hearings during hydro-project relicensing.
- Research in the Connecticut and Columbia rivers estimated up to 50 American shad per acre during the spawning run.
- Acres of available spawning habitat in the Susquehanna River were estimated and then multiplied by 50 shad per acre.
- The resulting estimate of two million shad represents how many spawning shad can be supported above the York Haven dam assuming effective fish passage downstream.
The James River restoration goal of 500,000 American Shad passed above Boshers Dam is based upon the number of shad that can be supported by the 137 miles (11,930 acres) that became available following construction of the Boshers Dam fishway.
- The number of acres was multiplied by 50 shad per acre, which is consistent with the Susquehanna River methodology and studies of the Connecticut and Columbia rivers.
- A total of 568,200 shad can be supported between Boshers Dam and Lynchburg, Virginia, including tributaries in between.
- The Boshers Dam fishway was sized to pass 500,000 shad annually.
York and Potomac River Shad Values
Values for the York and Potomac rivers are determined using gill-net data from the Virginia Institute of Marine Science, and pound net bycatch and discard data from the Potomac River Fisheries Commission. The 1950s commercial Catch per Unit Effort (CPUE) is compared to the current commercial (Potomac River pound net) or fishery-independent York River monitoring CPUE to determine achievement of goals.
Jennifer Greiner at 800-968-7229 ext. 783
Chesapeake Bay Program Office