alewife are anadromous, spawning in Virginia's freshwater streams and living as adults in saltwater
Source: US Fish and Wildlife Service, Alewife
Alewife (Alosa pseudoharengus), blueback herring (Alosa aestivalis), American shad (Alosa sapidissima), and hickory shad (Alosa mediocris) are anadromous fish. Adults migrate annually from the salty Atlantic Ocean into Tidewater rivers to spawn in freshwater.
The two herring species are so hard to distinguish in the water that they are commonly called "river herring." Alewife herring start spawning in late February, a month earlier than blueback herring. They migrate downstream after spawning, returning multiple times from the ocean to initiate a new generation. The young juveniles remain in freshwater streams until late Fall, when they swim downstream to the ocean or, in some cases, spend their first winter in the brackish water of the Chesapeake Bay.
Alewife and blueback herring can tolerate freshwater throughout their entire lives. Fishery managers have established reproducing populations in freshwater rivers, the Great Lakes, and reservoirs.1
fisheries managers have extended the distribution of alewife (Alosa pseudoharengus) to exclusively freshwater streams and lakes ("HUC"="hydrologic unit code")
Source: US Geological Survey (USGS), NAS - Nonindigenous Aquatic Species, Alosa pseudoharengus (Wilson, 1811)
Native Americans fished for river herring and shad using a variety of techniques. English colonists settling at Roanoke Island observed the use of "pound nets," which trapped fish as they swam underwater and provided a high amount of protein with minimal effort (other than installing and maintaining the net). Colonists adopted the same technique, as well as casting nets from boats or the shoreline to intercept schools of migrating fish.
pound net used in 1900, placed in Potomac River so fish swim in (at bottom) and get trapped
Source: Library of Virginia, Out of the Box, Don't Bush My Stand
George Washington's most profitable activity at Mount Vernon was his fishing operation. Claims that the shad run up the Delaware River in 1778 kept soldiers camped at Valley Forge from starving may be overstated, but one the migration started the fish must have been a welcome food source before the troops marched away in June.2
Source: YouTube, George Washington's Mount Vernon: Colonial Angling
The numbers of what were once very common anadromous fish in Virginia have dropped dramatically due to overfishing, habitat destruction, and limited access to breeding sites due to dam construction.
Populations are measured by a "catch index" - how many of fish are caught per net, per day. Since sampling started in 1998, the catch index for shad in the James River has ranged from 9.3 fish caught per net per day (in 2003) to 1.2 (in 2015). In the York River, the catch index dropped from 14.7 (in 1998) to 1.9 (in 2015). In the Rappahannock River, the low catch index of 1.3 (in 1999) climbed to a high of 8.7 (in 2014), then declined to 5.1 (in 2015).
A fish ecologist suggested that the variation was not a reflection of success or failure in efforts to restore shad. Instead, the numbers had been reduced dramatically from the typical population before the arrival of English colonists 400 years ago, and changes in the catch index were not significant compared to the massive reduction from the original base population:3
Native Americans make fishhooks by carving bone
Source: Virginia Humanities, Virginia Indian Archive, Bone Fish Hook
Efforts to increase shad populations include banning commercial harvest in 1994, removing dams that have blocked shad from migrating upstream to spawning habitat in Virginia rivers, and raising shad in hatcheries and releasing the young fish upstream of the old dams to start new populations that might return to the stocked sites. The Virginia Marine Resources Commission has established a moratorium on even recreational fishing for river herring:4
Maryland closed its commercial shad fishery in 1980. In 1982, the Potomac River Fisheries Commission (a joint program of both states) banned commercial fishing of shad in the Potomac River. It took Virginia until 1994 to end commercial fishing for shad in the state's portion of the Chesapeake Bay and inland waters. The James River shad harvest in 1993 was only 3,100 pounds, compared to 1 million pounds two decades earlier.
Source: PBS, Shad Run
The Atlantic States Marine Fisheries Commission (ASMFC) manages shad and river herring in the Atlantic Ocean. It closed the at-sea fishery for shad in 2005. The 2007 coastwide stock assessment will be updated in 2020 for American shad. The 2007 report:5
excessive harvest and habitat alteration dramatically reduced shad/river herring populations, forcing an end to most commercial harvest
Source: Atlantic States Marine Fisheries Commission, Shad and River Herring
The National Oceanic and Atmospheric Administration (NOAA) rejected a petition to add alewife (Alosa pseudoharengus) and blueback Herring (Alosa aestivalis) to the endangered species list in 2013. At the time, the harvest in the Chesapeake Bay had dropped 99% compared to the average in 1950-1970.
The Natural Resources Defense Council and Earthjustice appealed the reject, and in 2017 a Federal judge required the National Oceanic and Atmospheric Administration to reconsider the petition. A 2019 species status review determined that there were four "distinct population segments" of alewife on the East Coast, with the most-southern segment living between the Hudson River and the Alligator River in North Carolina.
one of the four "distinct population segments" of alewife on the East Coast swims in Virginia waters
Source: National Oceanic and Atmospheric Administration (NOAA), Status Review Report: Alewife and Blueback Herring (2019)
There are five distinct population segments of blueback herring. The middle population lives between the Connecticut River and the Neuse River in North Carolina.
In the status review, National Oceanic and Atmospheric Administration again declined to list those two species as "threatened." The Federal agency concluded that there was a 30% moderate risk of extinction for the distinct population segment of alewife that swim in Virginia waters. For blueback herring, there was a 30% moderate risk and a 1% high risk of extinction. The survival of the species was expected because:6
The latest report from the Atlantic States Marine Fisheries Commission remained pessimistic about river herring:7
Commercial "bycatch" harvest of the American shad in the Chesapeake Bay and some Virginia rivers waters is permitted, but prohibited in the Atlantic Ocean. In the spring, the shad migrate up to the Fall Line, and recreational fishing is permitted above the bycatch boundary line defined for the James, York, and Rappahannock rivers.8
bycatch area where commercial fishermen are authorized to possess some American shad
Map Source: ESRI, ArcGIS Online
Efforts to restore shad by stocking hatchery-raised fish have failed in Virginia, though the Potomac River population has remained relatively healthy. The Virginia Department of Game and Inland Fisheries invested in placing young shad in streams above dams that were going to be removed, to initiate a migrating population even while barriers were till in place and jump-start a recovery.
Shad were also stocked in the James River upstream of the fish ladder at Boshers Dam in Richmond. Young fish raised at the US Fish and Wildlife Service Harrison Lake Fish Hatchery in Charles City County were trucked to Scottsville for release.
hatchery-raised juvenile American shad were transported upstream to Scottsville, but the restoration program failed to increase populations in the James River
Source: ESRI, ArcGIS Online
Plans for releasing 10 million shad a year were constrained by the limited availability of female shad to provide eggs for the hatchery. Eggs from adult shad already migrating in the James River were preferred, but the hatchery supplemented them with eggs from shad migrating in the Pamunkey River and eventually the Potomac River. In the peak year (2000), 7 million fish were stocked.
Though in theory the re-stocking should have led to an increased population, the results were unsatisfactory. The Department of Game and Inland Fisheries decided in 2017 that the costs exceeded the benefits and ended the program. A fisheries biologist summed up the situation:9
In 2020, the Atlantic States Marine Fisheries Commission defined the shad population as "depleted." The construction of dams had blocked 40% of the spawning habitat, and only in the Rappahannock and York rivers were shad reproducing fast enough to sustain the existing low population numbers. Hatchery operations, limits on commercial fishing, and dam removal did not stimulate an expansion of the population.
One theory was that the invasive blue catfish and snakeheads were eating the young shad within the Chesapeake Bay, while other predators were eating the fish in the Atlantic Ocean. "Bycatch" of shad by commercial fishing boats targeting other species could also be a factor.10
American shad (Alosa sapidissima)
Source: US Fish and Wildlife Service, American Shad (by Duane Raver)
the Roanoke colonists observed how Native Americans used pound nets to catch herring, shad, and other types of fish
Source: Newberry Library, Their Manner of Fishynge in Virginia (by Theodor de Bry, 1590)