Chesapeake Bay

views updated May 29 2018

Chesapeake Bay

CHESAPEAKE BAY. By 1780, the Chesapeake Bay and its tributaries, lancing deep into the American countryside, seemed to fix the attention of Sir Henry Clinton, commander of the army that was attempting to subjugate Britain's thirteen rebellious colonies. Immediately following the conflict's eruption, skirmishes ashore and afloat had dotted the region, while a major British amphibious force raided the bay for two weeks with near impunity in 1779. As Clinton's southern campaign developed, especially following the capture of Charleston, South Carolina, the need for a deepwater port midway between the northern bastion of New York and the newly captured city seemed obvious. If such a port could serve as an enclave for recruiting local Tories, raiding rebel farms and plantations, or even regaining control of the colony, so much the better.

In late October 1780, the Royal Navy landed Major General Alexander Leslie and 2,500 men on the Elizabeth River with orders to establish a fortified harbor after raiding as far inland as Petersburg and Richmond, sites of major rebel supply depots. Leslie, finding virtually no support from local Loyalists, opted to seize the harbor at Portsmouth, Virginia, and to begin raiding only after fortifying it as his base. Before his entrenchments could be completed, General Charles Cornwallis, directly commanding British operations in the south, ordered Leslie to the Cape Fear region of North Carolina and then to Charleston to serve as a garrison force. By late November, the British presence in the Chesapeake Bay evaporated. Somewhat frustrated by Cornwallis's decision, Clinton immediately began planning another expedition to the region, issuing orders which would lead to the first of two major naval engagements and, eventually, to a world turned upside down.


On 11 July 1780, a French squadron of seven ships of the line, transports carrying around five thousand French soldiers, and supporting vessels anchored at Newport, Rhode Island. It posed little immediate threat to Clinton's strongly defended base at New York. Vice Admiral Marriot Arbuthnot, commanding the British fleet, did not fear to engage the French at sea, especially after reinforcements under Rear Admiral Thomas Graves arrived hard on the heels of the enemy force. The inherent strength of the British defensive positions at New York and the numerical superiority of Arbuthnot's ships of the line eliminated an immediate tactical threat, but the strategic location of Newport, with its difficult-to-blockade approaches, threatened to allow French interference with other British operations, especially in the south.

In truth, a quick amphibious assault against the French position may well have resulted in the utter destruction of the French forces, but their arrival found Clinton and Arbuthnot in the midst of an ongoing dispute over prize money dating to the capture of Charleston. Bitter feeling plagued their relationship, and neither was willing to give ground or full support to the other. In September, Admiral Sir George Rodney brought in the bulk of his fleet from the West Indies to avoid the hurricane season in the Caribbean. This worsened the rivalry, because Rodney refused to support either man and further alienated Arbuthnot by claiming overall naval command while in New York. Despite the tremendous naval superiority in American waters gained by Rodney's arrival, nothing had been accomplished by the time his fleet sailed back to the West Indies in mid-November except the stripping of spars, cables, and naval stores from New York.

With the departure of Rodney and the apparent return of Georgia and South Carolina to British control, Clinton determined to establish a permanent presence in Virginia. Brigadier General Benedict Arnold, late of the Continental army, landed at Westover, on the Chesapeake, on 4 January 1781. Within a matter of days, his forces had burned most of Richmond, Virginia, along with cannon foundries, supply depots, and anything else of value in the region. He then moved to Portsmouth, settling into the lines begun by Leslie the previous year. In late January, Arnold requested an additional 2,000 men, bringing his detachment to more than 3,500, for defense against the numerous rebels gathering around Portsmouth and to keep a raiding force active in the region. If he could not be reinforced, he suggested withdrawal to New York.

The danger posed by the French lodgment at Newport became evident in late January, when the 64-gun Eveille and two frigates escaped British blockaders. Graves, commanding the squadron on blockade, dispatched three ships of the line in pursuit. Caught by a harsh winter storm, the seventy-four gun HMS Bedford lost its masts, while HMS Culloden, another seventy-four gun ship, drove ashore on Long Island. Through heroic efforts its masts and rigging were saved to refit Bedford. The sixty-four gun HMS America was damaged in spars and hull and eventually returned to its anchorage. Meanwhile, the French raiders reached the Chesapeake, capturing a few merchantmen and the fourth-rate, 44-gun HMS Romulus. Without troops, however, the French could accomplish little against Arnold before returning to Newport.

Yet, the raid set forces in motion. The loss of Culloden and the addition of Romulus to the French squadron gave its commander, Captain Charles-Rene-Dominique Gochet Destouches (serving as commodore of the squadron since the loss of his admiral to fever), equality in hulls, if not in armament. It also encouraged General George Washington to dispatch Major General Marquis de Lafayette to the Chesapeake with 1,200 Continentals. By 3 March Lafayette's force rested on the Elk River, waiting hopefully for French naval transport to arrive. Meanwhile, as Arbuthnot worked feverishly to repair his ships from the same dockyard that had been stripped a few months previously by Rodney's vessels, Clinton organized men and transports to reinforce Arnold. Captain Destouches worked just as feverishly, cramming 1,120 soldiers with their equipment and supplies aboard his warships.

Major ships engaged at Chesapeake Bay
British shipsGunsCaptainsFrench ShipsGunsCaptains
Robust74Phillips CosbyNeptune74De Medine
Com. Des Touches
Europe64Smith ChildDuc de Bourgogne84Baron de Durfort
Prudent64Thomas BurnettConquerant74De la Grandiere
Royal Oak74William Swiney
Vice-Adm. Arbuthnot
London98David Graves
Rear-Adm. Graves
Ardent64De Marigny
Adamant50Gideon JohnstoneJason64De la Cloceterie
Bedford74Edmund AffleckEveille64De Tilly
America64Samuel ThompsonRomulus44De Villebrune

Destouches and his squadron—seven ships of the line, the fourth-rate Romulus, the sixty-four gun Fantasque armed en flute and two frigates—sailed on 8 March. Their disappearance was discovered by the British the following day. Arbuthnot's squadron—seven ships of the line, the fourth-rate Adamant, and three frigates—completed its repairs and upped anchor on 12 March. Clinton's transports, filled with over 2,000 men and their supplies and escorted by eight warships, followed on 20 March.


Heavy seas, strong wind, and variable visibility marked 16 March 1781 in the Atlantic waters off the entrance to Chesapeake Bay. Around 0600 hours, the frigate Iris, covering the rear of the British squadron, signaled the presence of the French force astern. The coppered bottoms of the British ships, which retarded the growth of weed and other sea life that could reduce ship speed, had allowed them to outpace the French ships, many of which lacked this maritime innovation. With the wind from the west, Arbuthnot immediately maneuvered to seek the weather gauge (a ship standing between the wind and an enemy ship is said to have the weather gauge, because it can determine the pace of the subsequent engagement). By 7 a.m., both squadrons had moved from their loose sailing formations to lines of battle (see table).

In each squadron's case, the line of battle would stretch for a mile on a day when visibility often fell below that distance. As to the lesser ships in the action, Iris maintained watch over the French, while Arbuthnot stationed his remaining frigates as repeaters (flag officers often stationed ships too small to stand in the line of battle on the side of the squadron away from the enemy in order to repeat flag hoists to the squadron). The French frigates apparently covered the Fantasque during the action. As usual in such affairs, all stood clear of enemy broadsides that could shatter or sink them in an instant.

Initially, Destouches, his ability to work or fight his ships impaired by the soldiers crowding their decks, sought to avoid action by fleeing northeastward. As the faster British fleet steadily reduced his lead and the wind began to veer to the north then to the northeast, Destouches surrendered to the inevitable and wore his ships to face the British. By noon both fleets bore southeastward, with the French holding the weather gauge and Robust rapidly drawing abreast of Romulus.

Usually, holding the weather gauge provided a strong advantage. However, with heavy seas and strong winds, as on 16 March, a ship heeling to the wind buried its lower-deck gunports on the leeward side (the side away from the wind) in the waves, rendering those guns unusable. Destouches, realizing that the weather gauge merely increased British superiority in guns, decided to surrender it to the enemy. At 1: 30 p.m. hours he ordered his ships to wear in succession around the head of the British line to a roughly westerly course. Arbuthnot, his line already extended from the morning's maneuvers, wore his ships as well and gained the weather gauge at the price of losing his advantage in number of guns. By 1400 hours, both fleets sailed a parallel course toward the entrance to the Chesapeake Bay. Arbuthnot kept his signal for "Line Ahead" flying, (a flag hoist instructing all ships to sail in a single column) apparently waiting for the ships at the rear of his line to resume station and intervals before hoisting "Engage the Enemy Closely."

But shortly after 2. p.m., and for reasons unknown, Captain Phillips Cosby steered his Robust directly toward the Neptune. As French fire concentrated on the Robust, the Europe and Prudent turned out of line to support it. Very quickly, the British flagship and the London entered the fray as well, clouds of smoke obscuring ships and signals. Unfortunately, Arbuthnot neglected to change his signal flag, and the remaining three British vessels, unaware of his desires, maintained their current course rather than closing in on the French rear.

Five British and eight French ships fought a chaotic battle inside the great cloud of smoke arising from their broadsides. British ships tended to fire at an enemy's hull, reducing their foe's firepower and weakening the ship's crew for eventual boarding. French doctrine called for the destruction of an enemy's rigging and masts, allowing French captains to eventually achieve a raking position, thus forcing the surrender of a drifting hulk. In this engagement, the upper-deck guns of Arbuthnot's ships fired with telling effect, as evidenced by the steady flow of blood from the scuppers of Conquerant, but French practice triumphed as the Robust, Europe, and Prudent soon drifted from the action with their rigging, spars, and even masts shot away.

Less than an hour after the first shot, Destouches decided to preserve his squadron and broke off southward. Arbuthnot, with damage to spars and sails on the Royal Oak and London almost as severe as that of his three lead ships, could not pursue. Instead he limped into Chesapeake Bay, securing it for the reinforcement convoy's eventual arrival.


Although Destouches clearly outperformed Arbuthnot in what came to be known as the battle of Cape Henry, he failed to secure the Chesapeake Bay for the Franco-American cause. Yet, Destouches's decision to abandon the action even after his maneuvers and British confusion provided a decided advantage is understandable. His ships, though in no danger of foundering, had been roughly handled by British broadsides. A continuation of the action may have resulted in a major victory, but the French navy lacked a dockyard in North America to repair damage to the squadron, much less any prizes captured. A Pyrrhic victory would have left the reduced and damaged French squadron blockaded, whether at an anchorage in the Chesapeake or at Newport. The soldiers packed between the decks of the French ships also weighed heavily on Destouches's mind. A protracted battle would have seen even more of them dead, perhaps in their hundreds, when delivering those same troops actually formed the core of his mission.

By denying the Chesapeake to the French, Arbuthnot won a tactical victory despite his poor performance in the battle. An admiral exists to control squadron and fleet operations. By failing to engage his entire fleet against the French line, Arbuthnot came very close to defeat. Even so, his tactical victory contributed to a strategic fallacy. By securing the Chesapeake, Arbuthnot validated Clinton's enclave strategy. That validation ultimately led directly to the British defeat at Yorktown, wherein another British fleet failed to gain control of the bay. In the final analysis, neither side lost ships during the engagement. The British suffered 30 killed and 73 wounded. The French, because of crowded conditions and the British concentration on hull damage, lost 72 killed and 112 wounded.

SEE ALSO Arbuthnot, Marriot; Destouches, Charles René Dominique Sochet; Graves, Thomas; Naval Operations, British; Naval Operations, French; Rodney, George Bridges.


Clowes, William Laird. The Royal Navy: A History from the Earliest Times to 1900. Vol. 3. London: Sampson, Low, Marston, 1898.

Dull, Jonathan R. The French Navy and American Independence: A Study of Arms and Diplomacy, 1774–1787. Princeton, N.J.: Princeton University Press, 1975.

Gardiner, Robert, ed. Navies and the American Revolution, 1775–1783. Annapolis, Md: Naval Institute Press.

Larrabee, Harold A. Decision at the Chesapeake. New York: Clarkson N. Potter.

Mackesy, Piers. The War for America, 1775–1783. Cambridge, Mass.: Harvard University Press, 1964.

Mahan, Alfred T. The Influence of Sea Power Upon History, 1660–1783. Boston, Mass.: Little, Brown, 1890.

Palmer, Michael A. Command at Sea: Naval Command and Control since the Sixteenth Century. Cambridge, Mass.: Harvard University Press, 2005.

Rodger, N.A.M. The Command of the Ocean: A Naval History of Britain, 1649–1815. New York and London: W.W. Norton, 2004.

Syrett, David. The Royal Navy in American Waters, 1775–1783. Aldershot, U.K.: Gower Publishing, 1989.

Tilley, John A. The British Navy and the American Revolution. Columbia: University of South Carolina Press, 1987.

                             revised by Wade G. Dudley

Chesapeake Bay

views updated May 08 2018

Chesapeake Bay

The Chesapeake Bay is North America's largest estuary and has a shoreline of more than 12,800 kilometers (8,000 miles). The bay is a long, narrow arm of the Atlantic Ocean that extends northward into Maryland and cuts the state into two parts. In addition to Maryland, the Chesapeake Bay drainage basin includes parts of the states of West Virginia, Virginia, Pennsylvania, New York, Delaware, and the entire District of Columbia. The cities of Richmond, Virginia; Washington, D.C.; and Annapolis, Maryland lie within its basin boundary.

Commodities have been exported and imported through the Chesapeake Bay since the Jamestown settlers inhabited the area in the early eighteenth century. Exporting and importing a multitude of goods today is a competitive business. Important deep-water navigable ports on the bay include Baltimore, Maryland, and Norfolk, Newport News, and Portsmouth in Virginia.

With deep-sea vessels containing equipment of the latest marine technology, U.S. companies can export large volumes of goods to other countries in a short period of time. The most profitable commodities imported into the Chesapeake Bay area include natural rubber, paper, auto parts, steel, iron, alcoholic beverages, grain, and tobacco. The strongest trade partners for the Chesapeake Bay include Brazil, Colombia, Venezuela, Japan, Greece, the United Kingdom, and Germany.

The Basin and Bay

Chesapeake Bay is approximately 323 kilometers (200 miles) long as it extends from Norfolk, Virginia to Havre de Grace, Maryland. The bay ranges in width from between 5.5 kilometers (3.4 miles) near Aberdeen, Maryland, to 56 kilometers (35 miles) near the mouth of the Potomac River. The mouth of the Chesapeake Bay is a narrow passage19 kilometers (12 miles) widebetween its northern point (Atlantic side) near Cape Charles, Virginia, and its southern point (inland side) close to Cape Henry, Virginia.

The Chesapeake Bay estuary receives approximately 50 percent of its water from the Atlantic Ocean, in the form of salt water. The other half of the water (fresh water) drains into the bay from a large 165,800-square-kilometer (64,000-square-mile) drainage watershed. Among the 150 major rivers and streams in the Chesapeake Bay drainage basin are the James, Potomac, York, Rappahannock, Patuxent, and Susquehanna. The Susquehanna River, located on the northern shore of the bay, provides about half of the fresh water coming into the bay, an amount totaling about 72 million liters (19 million gallons) of water per minute. The Chesapeake Bay contains on average more than 68 trillion liters (18 trillion gallons) of water.

Chesapeake Bay, the largest of 130 estuaries in the United States, is a complex ecosystem that includes important habitats and food chains . The bay supports more than 3,600 species of animals, plants, and fish, including 348 species of finfish, 173 species of shellfish, and over 2,700 plant species. Fish of all types and sizes either live in the bay and its tributaries, or they use the waters as they migrate along the East Coast. Every year, 1 million waterfowl rest in the bay's basin as they migrate along the Atlantic Migratory Bird Flyway. More than 500,000 Canada geese winter in and near the bay.

The Chesapeake Bay is a commercial and recreational resource for more than 15 million people who live in and near its watershed (drainage basin). The bay produces approximately 500 million pounds of oysters, crabs, and other seafood per year. The richness of its species can be seen in the value of the bay's annual fish harvest, which is estimated at over $100 million. It yields more oysters and soft-shelled crabs than any other region in theUnited States. The Chesapeake Bay is the largest producer of blue crabs in the world, although this fishery has recently experienced declines.

Environmental Concerns

Since the early twentieth century, the Chesapeake Bay has experienced serious environmental degradation. Problems include large reductions in sea grass, reduced amounts of finfish and shellfish (especially oysters and crab), seasonal depletions in dissolved oxygen, and increases in sedimentation .

Environmental concerns were voiced in the 1970s over the damage to key habitats and the decline in water quality. Species in bay waters were being negatively affected, resulting in threats to the commercial and recreational activities.

Most marine scientists believe that these changes are related to ecological stress due to increased human activities. Causes include deforestation, agriculture (including fertilizers), urbanization, pollution , and sewage. The Chesapeake Bay Commission predicts that by the year 2020, the population of the bay watershed will increase to 17.4 million. Without additional environment attention on the bay ecosystems, the Commission predict that stress on the natural system will increase dramatically.


One serious pollution problem in Chesapeake Bay has been eutrophication caused by excessive nitrogen and phosphorus. The increased fertility of the bay's waters has caused prolific algal blooms. Algal concentrations in the water column and dense mats of vegetation on the water surface can shade out native aquatic plants. The oxygen depletion resulting from the massive algal die-off disrupts the balance of the ecosystem. The primary sources of nitrogen and phosphorous have been the fertilizers and animal wastes of farmlands in the basin.

Toxic Contamination.

Toxic chemicals are entering the Chesapeake Bay and its food chain. These poisonous chemicals come from several point and nonpoint sources including industrial discharges, oil spills, agricultural runoff, urban runoff, and rainfall. Metals such as cadmium, copper, chromium, lead, nickel, and zinc are polluting the bay. In 1975, the massive release of the pesticide, Kepone®, into the James River in Virginia was one of the worst toxic inputs into the bay's ecosystem.

Most toxic substances persist in the Chesapeake Bay environment for many years, and have adverse affects throughout its food chain. One factor that complicates this situation is the bay's long residence time and low flushing rate. Only 1 percent of the settleable waste that enters the Chesapeake Bay is flushed to the ocean. The remainder settles in the bay's waters to form bottom sediment. Toxic contamination has been a prime suspect in the demise of several species in the bay.

Blue Crab.

One particular ecological concern is the blue crab, a popular commercial fish within the Chesapeake Bay. The 2001 Chesapeake Bay commercial blue crab harvest of approximately 52 million pounds was well below the average of about 75 million pounds that has annually occurred from 1968 to 2001.

Analysis of long-term fishery independent surveys conducted in the Chesapeake Bay indicate that the blue crab population is approaching a record low after declining in recent years. The low numbers places the blue crab at increased risk for not rebounding. With low population numbers combined with a high fishing catch rate, the blue crab continues to be a great concern.

Mute Swans.

Mute swans, native to Europe and Asia, were transported to North America in the late nineteenth century by European immigrants. Some swans eventually escaped or were deliberately released into the wild. In Maryland, the mute swan population grew from five captive swans that escaped in 1962 to more than four thousand swans as of 2000.

Because mute swans did not evolve with the native species in Chesapeake Bay, these aggressive invaders have caused many problems. Mute swans are suspected of causing a 30-percent decline in Maryland's wintering population of tundra swans. In the early 1990s, mute swans caused a colony of least terns and black skimmers (both threatened species in Maryland) to abandon their nesting site. Mute swans overgraze bay grasses, eliminating habitats for crabs, fish, and other species.

Some mute swans are aggressive and will attack humans, including small children, in defense of their nest territory and cygnets (their offspring). This territorial behavior can be a nuisance, and renders some land and water areas inaccessible to people during the swan nesting and brood-rearing season. Swans have even been documented killing mallard ducklings and Canada goose goslings.

Since the mid-1990s, the Maryland Department of Natural Resources, along with some federal agencies, has taken measures to control mute swan populations. In 1998, Maryland's governor appointed a committee to develop mute swan management recommendations. In 2002, the management plan was in its public comment period. The recommendations combine lethal and nonlethal methods intended to reduce the mute swan populations to levels compatible with native wildlife, natural ecosystems, and human environments.

Saving the Bay

Due to impacts from serious environmental threats, the U.S. Environmental Protection Agency (EPA) recognized the Chesapeake Bay as a damaged ecosystem. The EPA conducted a $27 million research study from 1976 to 1983. This study concluded that immediate and intensive efforts were needed to save this estuary and restore its ecological health. In 1983, the Chesapeake Bay Agreement was signed and the federal government and the states of Maryland, Virginia, and Pennsylvania, and the District of Columbia pledged to take action to reverse its environmental deterioration.

These actions included upgrading sewage treatment plants, controlling urban runoff, controlling manure and fertilizer runoff, reducing soil erosion, issuing stricter discharge permits, and banning the use of phosphorous detergents. This agreement outlined the goal of reducing the amounts of nitrogen and phosphorus entering the bay by 40 percent by the year 2000. These strategies have had some measurable success in saving the bay. The Chesapeake Bay Agreement has been amended in 1987, 1992, and 2000. These agreements reflect the ongoing political process of strengthening regional efforts to save the bay.

Two important organizations working toward an improved Chesapeake Bay environment are the Chesapeake Bay Program and the Small Watershed Grants Program.

Chesapeake Bay Program.

The Chesapeake Bay Program is a partnership among the states of Maryland, Virginia, Pennsylvania, the District of Columbia; along with the Chesapeake Bay Commission and the federal government. It was formed in 1983 as a result of the first Chesapeake Bay Agreement. The partnership has stated a number of bay protection and restoration goals, and it strives to mobilize the resources of the governmental sector with the private sector to achieve its goals. The Chesapeake Bay Program operates as a voluntary, collaborative resource management program. It has set goals related to fisheries, wetlands , submerged grasses, nutrient reduction, toxins, sustainable development, and citizen involvement.

Small Watershed Grants Program.

The Small Watershed Grants Program provides grants to organizations working on a local level to protect and improve watersheds in the Chesapeake Bay basin, while building citizen-based resource stewardship. The purpose of the grants program is to emphasize the water quality and living resource needs of the Chesapeake Bay ecosystem. The Small Watershed Grants Program has been designed to encourage the development and sharing of innovative ideas among the many different types of organizations involved in watershed protection activities.

Concerted efforts are being made to improve the ecological health of the Chesapeake Bay. While progress has been made, the recovery of this resource will require long-term effort and the active participation of all six states and the District of Columbia lying within its drainage basin. Given projected population increases, these efforts to control nutrient and chemical discharges into its rivers and to improve waste treatment technologies are vital to protecting the water, habitat, and species of this estuary ecosystem.

see also Algal Blooms in Fresh Water; Algal Blooms in the Ocean; Bays, Gulfs, and Straits; Crustaceans; Ecology, Marine; Estuaries; Pollution by Invasive Species; Ports and Harbors; River Basin Planning; Transportation; Watershed, Restoration of a.

William Arthur Atkins

Faye Anderson


Dorbin, Ann E. Saving the Bay: People Working for the Future of the Chesapeake. Baltimore, MD: Johns Hopkins University Press, 2001.

Internet Resources

Chesapeake Bay Blue Crab Advisory Report 2002. Chesapeake Bay Stock Assessment Committee. <>.

Chesapeake Bay Commission. <>.

Chesapeake Bay Program: America's Premiere Watershed Restoration Partnership. Chesapeake Bay Program, Chesapeake Information Management System. <>.

Ecosystem Trends and Response: Chesapeake Bay. U.S. Geological Survey. <>.

EPA Chesapeake Bay Program Office. <>.

Chesapeake Bay

views updated May 08 2018

Chesapeake Bay

The Chesapeake Bay is the largest estuary (186 mi [300 km] long) in the United States. The Bay was formed 1500 years ago by the retreat of glaciers and the subsequent sea level rise that inundated the lower Susquehanna River valley. The Bay has a drainage basin of 64,076 square miles (166,000 sq km) covering six states and running through Pennsylvania, Maryland, the District of Columbia, and Virginia before entering the Atlantic Ocean. While 150 rivers enter the Bay, a mere eight account for 90% of the freshwater input, with the Susquehanna alone contributing nearly half. Chesapeake Bay is a complex system, composed of numerous habitats and environmental gradients.

Chesapeake Bay's abundant natural resources attracted native Americans, first settling on its shores. The first European record of the Bay was in 1572 and the area surrounding Chesapeake Bay was rapidly colonized by Europeans. In many ways, the United States grew up around Chesapeake Bay. The colonists harvested the Bay's resources and used its waterways for transportation . Today 10 million people live in the Chesapeake Bay's drainage basin, and many of their activities affect the environmental quality of the Bay as did the activities of their ancestors.

The rivers emptying into the Bay were also used by the colonists to dispose of raw sewage. By the middle 1800s some of the rivers feeding the Bay were polluted: the Potomac was recorded as emitting a lingering stench. The first sewer was constructed in Washington, DC, and it pumped untreated waste into the Bay. It was recognized in 1893 that the diseases suffered by humans consuming shellfish from the Bay were directly related to the discharge of raw sewage into the Bay. Despite this recognition, efforts in 1897 by the mayor of Baltimore to oppose the construction of a sewage system that discharged sewage into the Bay in favor of a "land filtration technique" failed. Ultimately, a secondary treatment system discharging into the Bay was constructed. In the mid-1970s, a $27 million government-funded study of the Bay's condition concluded that the deteriorating quality of the Chesapeake Bay was a consequence of human impacts. But it was not until the early 1980s that an Environmental Protection Agency (EPA) report on the Chesapeake focused interest on saving the Bay, and $500 million was spent on cleanup and construction of sewage treatment plants.

While the Chesapeake Bay is used primarily as a transportation corridor, its natural resources rank a close second in importance to humans. The most commercially important fisheries in the Bay are the native American oyster (Crassostrea virginica ), blue crab (Callinectes sapidus ), American shad (Alosa sapidissima ), and striped bass (Marone saxatilis ). Fisherman first began to notice a decline in fish populations in the 1940s and 1950s, and since then abundances have declined even further. Since the turn of the century, the oyster catch has declined 70%, shad 85%, and striped bass 90%. In the late 1970s, the EPA began to study the declining oyster and striped bass populations and concluded that their decline was due to a combination of over-harvesting and pollution .

Work by the EPA and other federal and state agencies has identified six areas of environmental concern for the Bay: (1) excess nutrient input from both sewage treatment plants discharging into the Bay and runoff from agricultural land; (2) low oxygen levels as a result of increased biochemical oxygen demand , which increases dramatically with loading of organic material; (3) loss of submerged aquatic vegetation due to an increase in turbidity; (4) presence of chemical toxins ; (5) loss to development of wetlands surrounding the Bay that serve as nurseries for juvenile fish and shellfish and as buffers for runoff of nutrients and toxic chemicals ; and (6) increasing acidity of water (measured by pH ) in streams that feed the Bay. These streams are also nursery areas for larval fish that may be adversely affected by decreasing pH.

The increasing growth of phytoplanktonfree-floating single-celled plantsin the Bay is generally considered to be a significant contributor to the decline in environmental quality of the Chesapeake Bay. The number of algal blooms has increased dramatically since the 1950s and is attributed to the high levels of the plant nutrients nitrogen and phosphorus that are discharged into the Bay. In the 1980s and 1990s, it was estimated that discharge from sewage treatment plants and agricultural runoff accounted for 65% of the nitrogen and 22% of the phosphorus found in the Bay. Acid rain , formed from discharges from industrial plants in Canada and the northeast United States, contributed 25% of the nitrogen found in the Bay. Excess nutrients encourage phytoplankton growth, and as the large number of phytoplankton die and settle to the bottom, their decomposition robs the water of oxygen needed by fish and other aquatic organisms. When oxygen levels fall too low, these organisms die or flee from the regions of low oxygen. Decomposition of dead organic matter further reduces the concentration of oxygen. During the late twentieth and early twenty-first centuries, Finfish and shellfish kills became increasingly common in the Bay.

Phytoplankton blooms and the increase in suspended sediments resulting from shoreline development and poor agricultural practices have increased turbidity and led to a decline in submerged aquatic vegetation (SAV) such as eelgrass . SAV is extremely important in the prevention of erosion of bottom sediment and as critical habitat for nursery grounds of commercially important fish and shellfish.

Chemicals introduced into the Bay from several sites may have contributed to the decline in the Bay's fish and bird populations. For example, in 1975, the pesticide Kepone was leaked or dumped into the James River, poisoning fish and shellfish. Harvests of some species are still restricted in the area of this spill. Chlorine biocides used in wastewater treatment plants and power plants , which discharge into the Bay, are known human carcinogens and can be toxic to aquatic organisms. Polycyclic aromatic hydrocarbons (PAH) have caused dermal lesions in fish populations in the Elizabeth River. PAHs also affect shellfish populations. In the 1990s, public concern focused on tributyl tin (TBT) that was used in anti-fouling paint on recreational and commercial boats. TBTs belong to a family of chemicals known as organotins, which are toxic to shellfish and crustaceans. The diversity of chemical pollutants found in the Bay is exemplified by the results of research that identified 100 inorganic and organic contaminants in striped bass caught in the Bay. As of 2002, research efforts were underway to determine the extent of the damage from toxins to natural resources.

Work by private and governmental agencies has started to reverse the declining environmental quality of the Chesapeake Bay. In 1983 Maryland, Virginia, Pennsylvania, the District of Columbia, the Chesapeake Bay Commission, and the EPA signed the Chesapeake Bay Agreement, which outlined procedures to correct many of the Bay's ecological problems, particularly those caused by nutrient enrichment. In 1987 the agreement was significantly expanded and required that the signatories adopt a strategy that would result in at least a 40% reduction in nitrogen and phosphorus entering the Bay by the year 2000. Since 1985, increasing compliance with discharge permits, prohibition of the sale of phosphate-based detergents , and the upgrading of wastewater plants has resulted in a 2% reduction in the discharge of nitrogen and a 39% reduction of phosphorous from point sources of pollution. Controls on agriculture and urban development have resulted in approximately 7% reductions in the amount of both nitrogen and phosphorus entering the Bay from nonpoint sources. The amount of toxins entering the Bay have also been reduced. Tributyl tin has been banned for use in anti-fouling paints on non-military vessels, pesticide runoff has been reduced by using alternate strategies for pest control, and since 1987, toxic emissions from industrial sources have declined more than 40%. At the same time, some of the Bay's critical habitats are recovering: 22,000 more acres of SAVs are now growing than in 1984, although the total amount of 60,000 acres is still a fraction of the estimated 600,000 acres the historical SAV distribution, man-made oyster reefs are being created to expand suitable habitat for oysters, and rivers are being cleared of obstacles such as dams and spillways to provide access to spawning areas by migratory fish.

Conflict between commercial and environmental interests have encumbered some of the restoration efforts. Research on the life-history of crabs and oysters shows that limiting the size of crabs that can be sold and the numbers of oysters that can be harvested will help these fisheries rebound, but regulations to limit crab and oyster catches have met with strong resistance from watermen who are struggling to survive economically in a declining fishery.

The planned introduction of a non-native Asian oyster (Crassostrea ariakensis ) by the Virginia Seafood Council, raised hopes that a new oyster fishery could be built around the harvest of this disease-resistant, fast-growing species. In May 2002, the United States Fish and Wildlife Service called for a moratorium on the introduction of the Asian oyster, until researchers could determine whether its introduction would endanger native species, or bring new and deadly disease organisms into Chesapeake Bay. A study by the National Academy of Sciences was commenced in 2001 with the goal of making information on these concerns available in summer of 2003.

As of 2002, portions of Chesapeake Bay and its tributaries were still listed as impaired waters under Section 303(d) of the Clean Water Act , but progress on arresting the decline of environmental quality of Chesapeake Bay and restoring some of its natural resources continued. In the Chesapeake 2000 Bay Agreement (C2K), Maryland, Pennsylvania, Virginia, and the District of Columbia, together with the Chesapeake Bay Commission and the Federal Government committed to "correct the nutrient- and sediment-related problems in the Chesapeake Bay and its tidal tributaries sufficiently to remove the Bay and the tidal portions of its tributaries from the list of impaired waters under the Clean Water Act." This consortium of stakeholders, jurisdictions, and federal agencies is evidence that citizens, government, and industry can work cooperatively. The Chesapeake Bay program is a national model for efforts to restore other degraded ecosystems.

[William G Ambrose Jr. and
Paul E Renaud and
Marie H. Bundy



Brown, L. R. "Maintaining World Fisheries." In State of the World, edited by L. Starke. New York: Norton, 1985.

Majumdar, S., et al. Contaminant Problems and Management of Living Chesapeake Bay Resources. Easton, NJ: Typehouse of Easton, 1987.


D'Elia, C. "Nutrient Enrichment of the Chesapeake Bay." Environment 29 (1987): 6-11.


Chesapeake Bay Foundation, Philip Merrill Environmental Center, 6 Herndon Avenue, Annapolis, MD 21403 410/268-8816, Email:

Chesapeake Bay

views updated Jun 08 2018

Chesapeake Bay Inlet of the Atlantic Ocean in Virginia (s) and Maryland (n), USA, at the mouth of the Susquehanna River. Linked to the Delaware River by the Chesapeake and Delaware Canal, the first permanent English settlement in North America was on Chesapeake Bay, at Jamestown, Virginia, (1607). In 1608 John Smith explored and charted the bay. Length: 311km (193mi). Width: 5–40km (3–25mi).