Geoscience Reference
In-Depth Information
chovies, and even oysters. From this list of predator and prey, it is clear that blue crabs are connected to all
levels of the food web, and so changes in their numbers have ripple effects throughout the system.
QUAHOG
IN 1936, RACHEL CARSON wrote: “Just as the sacred cod of Massachusetts is the accepted emblem of [that]
state, so the shad may rightly be considered the piscatorial representative of the states bordering the Ches-
apeake.” The famed New Yorker staff writer John McPhee went further, arguing that the American shad was
“the founding fish” of the United States. In the fourth spring of the American Revolution, George Washington,
himself a commercial shad fisherman, bivouacked his army on the banks of the Schuylkill River. Historians
believe that the founding father knew exactly what he was doing, because the spring run of fat shad reputedly
saved his men from starvation.
The American shad is the largest member of the herring family, ranging in weight from 1 to 4 kilograms (2
to 8 pounds) and, though bony, is justly famed for its culinary qualities, which earned it the species name sapi-
dissima, or “most delicious.” Herring and shad were the basis of the first commercial fisheries in the Ches-
apeake Bay, and on the Potomac River alone, six thousand fishermen harvested these two species in the 1830s.
Large spawning populations once reached far into the hinterland of Chesapeake's waters, where they were also
important food sources for the settlers of these regions. Shad migrated up the Susquehanna River as far as New
York State and reached the foothills of the Blue Ridge Mountains via the mighty James River.
Much of the spawning territory on these and many other spawning rivers along the eastern seaboard was lost
in the 19th century to dams. The Chesapeake Bay writer Tom Horton has observed that these dams created
“the amputated bay,” in which thousands of kilometers of spawning territory was cut off with predictable res-
ults—a collapse of shad stocks. It was not until the last decade of the 20th century that the situation was cor-
rected with the building of more than a hundred fish ladders and the removal of nearly forty dams. As a result
of these steps, in concert with an ambitious restocking program and a moratorium on commercial fishing of
stocks as they migrate along the coastlines of Virginia and Maryland, the shad has made a strong comeback. Its
smaller relative, the alewife, or river herring, has also benefitted from these measures, since it makes spawning
runs on many of the same rivers as the shad.
Shad are main-stem spawners, preferring to spawn in relatively broad, shallow, and slow moving sections of
their natal rivers, whereas alewives often move into smaller tributaries and streams, where they also choose
sluggish rather than fast-moving sections in which to deposit their spawn. Both shad and alewives are plankti-
vorous, though they sometimes consume very small fish too. At all of their life stages, these anadromous
alosines, which also include the hickory shad and blueback herring, play an important role in the food webs of
freshwater, estuarine, and marine ecosystems and may also play a significant role in transferring nutrients from
the marine system to freshwater rivers.
Another fish, striped bass, has also long been identified with the Chesapeake Bay. Like shad, striped bass
are an anadromous species that spawn in fresh or brackish water and return to ocean waters. They are found
Search WWH ::




Custom Search