Understanding the Chesapeake Bay According to Two of its Most Tell-tale Inhabitants

This discussion topic submitted by Erin Latimer ( nitro151@vcu.org) at 10:43 pm on 6/8/00. Additions were last made on Saturday, August 26, 2000.

The Chesapeake Bay's current status reflects hundreds of years of human pollution, over use, and degradation. Because of the abundant resources the Bay has long been considered inexhaustible. Recently, however, this assumption has been proven wrong. Two important organisms, bay grasses (SAV) and bay oysters show the telltale signs of exhaustibility. Both have been dramatically reduced in mass since the bay area was first populated. All is not lost however for the Chesapeake Bay and its inhabitants, including the grass and oyster populations. Recent studies and concern have prompted new action from legislature. But it is clear that the actions and attitudes of all who reside in bay's watershed will have to change in order for any restoration programs to truly benefit the bay.

The ecosystem known as the Chesapeake Bay spans over 64,000 square miles and supports 15 million inhabitants. The watershed, or region whose water drains into the Chesapeake Bay, includes portions of Virginia, Maryland, New York, Delaware, Pennsylvania, West Virginia, and all of Washington D.C. Erosion and pollution throughout all of these areas eventually drains into the bay bringing its negative effects with it. As the population grows, an increase of three million is expected by the year 2020, the human destruction will only worsen. But the importance of the Chesapeake Bay should demand its preservation. The bay supports a variety of economic ventures for those who live around it, including shipbuilding and fishing. It is a major commercial waterway, but also attracts many recreational visitors to its shores for things like camping, hunting, and boating. It is famous for providing delicacies from within its waters, especially its blue crabs and oysters. But the most important aspect of the bay is the habitat it provides to the abundant wildlife living in its water and on its shores.

This habitat, which is home to numerous species of birds, fish, vegetation, and microorganisms to name a few, is directly affected by three factors: pollution, over harvesting, and its own resistance to these problems. The first problem is pollution. The bay is being over run with nutrients, toxic substances, and sediments from runoff throughout the watershed. While a healthy ecosystem necessitates nutrients for its survival, too many nutrients can create algal blooms that decrease sunlight required for the survival of underwater vegetation. This vegetation provides important habitats for underwater organisms. The death of these algal blooms creates another issue, elimination of dissolved oxygen in the environment. This can destroy the entire ecosystem creating a dead zone where no living beings can survive.

Another important issue facing the Chesapeake Bay is the over harvesting threat to the fin and shellfish populations inhabiting its waters. A false confidence in the abundance of fish produced by the bay led to an over fishing normality unregulated and unchecked by any authority. Fish stocks were completely decimated for years until research finally proved that over fishing really was the problem. Catch limits, already put in place, have proven to be successful in regulating these populations. Although these populations are now being regulated according to recent numbers of abundance, some species might take many more years or might never replenish themselves to their original state. An example is the bay oyster whose numbers have been reduced to merely one percent of their original population. At one time, before the nineteenth century, oyster reefs were so abundant that they were considered navigational hazards but over harvesting, disease, and loss of habitat has changed this. With over harvesting and pollution being two eminent threats the question becomes, how will the bay handle this? Well, as the populations of oysters, bay grasses, and surrounding habitats are destroyed so are the chances that the bay will be able to recuperate on its own. These are the very filtering systems of the bay ecosystem and their loss destroys any hope that the bay can save itself.

One of the crucial filtering systems mentioned above is the bay grass beds of the Chesapeake Bay also known as SAV, submerged aquatic vegetation. These grasses use the nutrients whose abundance causes algal blooms, they filter sediments that would otherwise reduce available sunlight, and they produce oxygen for use by other organisms. But these are just a few of the importances that the bay grasses provide to the ecosystem. They also provide shelter, refuge, and food to other aquatic organisms as well as protecting shorelines from erosion. But their enormous decline throughout history limits their ability to perform these tasks. While originally 600,000 acres of shoreline were home to SAV beds, now only 68,125 acres are estimated bay wide. And this number is up from a 1998 decline of 5, 740 acres.

This overall decline of underwater grass beds it due directly and indirectly to human activities within the watershed. These grasses require sunlight for photosynthesis and thus survival. As the Chesapeake Bay becomes more polluted light is blocked from reaching the plants and they are unable to flourish. Sediments enter the water through erosion and nutrient overflows produce algal blooms that also block the crucial sunlight. Pollution, erosion, and nutrient overflow are all consequences of human actions. These can be caused by land development, destruction of buffering wetlands, boat traffic, acid rain, fertilizer draining into the bay, and so on. If these threats to the bay grass ecosystem are left unchecked it could mean the destruction of these beds for good, however, steps are already being made in the right direction.

Chesapeake 2000 is a renewed version of the Chesapeake Bay Agreement signed in 1993 and partners Virginia, Maryland, Pennsylvania, Washington D.C., the Chesapeake Bay Commission, and the U.S. Environmental Protection Agency in an effort to restore the bay's grass beds. The goal is 114,000 acres by 2002, and this effort is 58% underway by the 1999 total. This act also includes measures to speed up grass growth in pertinent areas, and a plan for restoration to exceed previous hopes. Other issues of bed destruction, such as clam dredging are also being addressed as the General Assembly passes a bill prohibiting the use of hydraulic dredges in the bay. And more informally, mass plantings of grass beds are held for public participation and opportunities to survey existing beds are also offered. These efforts and regulations come well deserved to such an active and important part to the Chesapeake Bay ecosystem.

Another crucial member of the Chesapeake Bay's immune system is the historically abundant oyster. Once so abundant as to create navigational difficulties for sailors and produce millions of bushels in one season's harvest, now the oyster tells a different story. Today it takes an estimated one year for the oyster population to filter all the water in the bay, while at the height of their abundance it could have taken as little as three to four days! The oyster loss only increases the algae and nutrient contents of the bay and the lack of dissolved oxygen and increase sedimentation only increases the oyster loss. But the oysters hold more than one niche in the Chesapeake Bay ecosystem. The oysters and their reefs provide homes for smaller organisms and are a food source for humans and certain birds. But these important roles of the oyster are not being fulfilled due to their tremendous loss.

The oysters suffer from the same fate as the other organisms in the bay, including the bay grasses. Siltation due to erosion suffocates the oysters and prevents them from feeding, over harvesting has removed such large quantities that the oysters cannot replenish themselves naturally, and algal blooms have depleted available oxygen disabling oyster larvae growth. But the oysters suffer from other dangers not threatening to all of the members of the bay. Two parasites lethal to oysters but non-threatening to humans have succeeded in abolishing mush of the oyster population. MSX, which thrives in higher salinity, and Dermo, which thrives in lower salinity, both have decimated the oyster population, which is less able to nurse itself back to health due to already low numbers. Another issue for the oyster is predation. Normal in any ecosystem predation to the already low population of bay oysters can be deadly.

This decline in such an important species is not being ignored. The Virginia Oyster Heritage Program will launch a $3 million dollar program in effort to restore this lost population. Man-made oyster reefs are being built in attempt to mimic the real thing using disease resistant oysters. This concept began in 1993 with much skepticism but proved to be successful none the less. These reefs will be left alone to grow as no harvesting is allowed on the reefs. Other efforts include harvesting limits and restrictions, the most basic effort in restoring bay oysters. But research must continue in the area of disease for the oyster population to regain their former success.

While the destruction to the Chesapeake Bay has been going on for hundreds of years the restoration is only in its first stages of life. But the effort is there. A new program offers $90 million in the next fifteen years for farmers to plant trees in environmentally sensitive land in the bay area. This effort out does all previous efforts in cost and value. While the damage cannot be reversed over night at least the realization is there for the effort to get underway. Education must continue, as well as research, to inform every one of the dangers the bay may face without change. For chance to take place it requires an entire community with the understanding that each individual's actions can affect the state of the bay. The wheels are turning for improvement of SAV and oysters in the Chesapeake Bay, and it is definitely a resource worth watching to see where it goes.
"American Oyster." & "Bay Grasses." & "Introduction to an Ecosystem."
Harper, Scott. "Bay Regains Crucial Grass Beds." The Virginia Pilot, Norfolk, VA.
Harper, Scott. "State, federal officials announce program to restore oysters to
Chesapeake Bay." The Virginia Pilot, Norfolk, VA. 1999.

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