Downriver from the main effects of the metropolitan complexities, the
widening brackish and salt portions of the Potomac estuary form a
generally healthy body of water, though changes loom as the metropolis
moves inexorably outward from its center and as hitherto remote
Tidewater areas are brought more and more under the influence of modern
ways of being. Localized problems of pollution point to general dangers
that will certainly materialize unless safeguards are set up in time,
for estuaries are delicate, immensely productive, and still somewhat
mysterious aquatic environments that have been and still are too much
taken for granted.
[Illustration]
[Illustration]
Rapid human intrusion on estuaries during the past twenty years has
been making apparent their phenomenal value in a natural condition.
Vulnerable, attractive to diverse interests that work their beds for
sand and gravel and fill in their marshes for development and casually
pollute them, they have recently been called America's most endangered
natural habitat. They are almost unbelievably fertile places, with
involved biological cycles that can convert the fertility into usable
food at rates per acre far exceeding those of the finest farm land; in
terms of money, one recent set of experiments indicates the possibility
of attaining an annual shellfish production on tended beds worth over
$26,000 an acre.
Furthermore, aside from the direct harvest of this wealth from estuaries
each year by commercial and sport fishermen, these in-between waters
make an indispensable contribution to the entire Atlantic coastal
fishery, an industry worth a billion dollars a year. The reason for this
is that at least 70 percent of coastal fishes spend some essential part
of their life cycle within an estuary--spawning there, or passing
through on their way to spawn in running fresh streams, or moving in as
fry from the rivers or the open sea to find a "nursery" in one of the
varied estuarine habitats--bays, marshes, sandy shorelines, mudflats,
tidal creeks, or weed beds.
The oysters from the famous beds in the Saint Mary's River off of the
lower Potomac are mainly condemned as unfit for consumption because of
local sewage pollution, and these beds are not the only unfit ones, for
towns and resorts in the region have been growing and sanitary
facilities have not been keeping pace. Already some arms of the superb
natural harbors formed by the tributary creeks are noxious with
discharges from boats at big marinas, and gravel dredging is stirring up
silt to smother bottom life, including shellfish. As Tidewater
agriculture revives and modernizes, pesticides and artificial
fertilizers are coming to be as much a part of the scene there as in
other farming regions, and may be expected to influence the estuary--in
fact, they undoubtedly already are doing so in subtle ways with effects
not yet apparent.
Yet most of this part of the river is still beautiful and continues to
yield good harvests of seafood. The Potomac River Fisheries Commission
has been alert to obvious dangers and has moved against them where its
powers have permitted, and natives of the area are increasingly alert in
protecting the estuary. Many of them depend on it for a living, most are
oriented toward it for their pleasures, and until lately a good many of
them counted on it for transportation. In a number of different ways, it
matters in their lives. And that fact offers some hope for the future,
especially if it is fostered and strengthened by overall protective
measures.