he health of the Chesapeake Bay can be visually observed, says Pat Stuntz, assistant director of the Chesapeake Bay Commission, a tri-state legislative commission based in Annapolis that advises the general assemblies of Virginia, Maryland and Pennsylvania.
“Let’s face it, all you have to do is look at it. You can’t see one or two inches into it,” Ms. Stuntz says. “It sure doesn’t look healthy.”
The Chesapeake Bay, the nation’s largest estuary opening into the Atlantic Ocean, is polluted from various sources, including air pollution, chemical contaminants, erosion and nutrient runoff from farmland and paved surfaces. The population of oysters, the Bay’s major filtering device that helps clean up the water, declined significantly over the past 25 years, contributing to the Bay’s poor health.
“The Bay, in our bureaucratic lingo, is impaired. In other words, it doesn’t meet the water-quality standards that have been established to protect aquatic life,” says Alan Pollock, manager of water-quality programs for the Virginia Department of Environmental Quality in Richmond.
Several agencies, including the Environmental Protection Agency’s Chesapeake Bay Program, the Chesapeake Bay Foundation and the Chesapeake Bay Commission, all based in Annapolis, along with state departments of natural resources and of the environment, are implementing cleanup programs and are educating the public about what they can do to improve the health of the Bay.
The Chesapeake Bay Program’s 2006 report card, which analyzes water quality and habitat, graded the major tributaries with mostly D’s and D minuses, giving a C plus as the highest score, Ms. Stuntz says. The scores are among the worst since monitoring began in 1985, she says.
The low scores result from various problems in the Bay, including runoff of sediments and nutrients and a decline in natural filters, including oysters, forests and green, living vegetation, Ms. Stuntz says. Trees and vegetation capture sediment from runoff following a heavy rainstorm and filter out of the air nitrogen from power plants, automobiles and other sources, she says.
Nutrients in the runoff cause sun-blocking blooms of algae to grow, and, in turn, the blooms use up oxygen in the water when they decompose, Ms. Stuntz says. The sunlight is needed for underwater bay grasses to grow and the oxygen for underwater animals, she says.
“The fish and shellfish lose huge areas of the Bay for habitat because there isn’t sufficient oxygen for them to breathe,” she says.
Oysters act as filter-feeders and provide a habitat on the ocean bottom for small fish and crabs, says Jim Wesson, department head for conservation and replenishment for the Virginia Marine Resource Commission, a steward of Virginia’s marine and aquatic resources based in Newport News. He holds a doctorate in wildlife biology.
“Each oyster does a lot, but there’s not that many of them,” Mr. Wesson says. “They take sediments out of the water and put them on the bottom instead of being in the water column. They’re like vacuum cleaners when they feed.”
Oysters filter water through their gills, extracting algae and plankton, which are tiny, open-water plants, animals and bacteria, says Thomas O’Connell, assistant director of the Maryland Department of Natural Resources Fisheries Service in Annapolis. The population of oysters from 1800 to the early 1900s had the ability to filter the entire volume of the Bay every three days, and now it takes thousands of days to perform the same task, he says.
“Anything living in the Chesapeake Bay needs healthy water. Now, we don’t have enough healthy water for species to survive,” says Stephanie Reynolds, fisheries scientist for the Chesapeake Bay Foundation, a nonprofit organization dedicated to restoring and protecting the Chesapeake Bay and its tributary rivers.
The oyster populations began decreasing in the 1900s from overharvesting but stabilized by mid-century, Mr. O’Connell says. In the 1980s, two parasites that are harmless to humans but deadly to oysters further lowered their numbers, which now are at 1 percent of historic levels, he says.
The loss of the oyster population has significantly affected the oyster industry, resulting in a decrease in the number of boats working the Bay from the thousands to the tens, Mr. Wesson says.
The harvest has decreased from 5 million bushels a year in Virginia and Maryland from 1920 to 1970 to fewer than 200,000 bushels a year, Mr. O’Connell says.
“It used to be a thriving industry. Now, just a few watermen participate,” he says.
At one time, oyster harvesting provided watermen with a steady livelihood during the winter months when other fishing was not available, Mr. O’Connell says.
Maryland, Virginia and the U.S. Army Corps of Engineers in Northwest began developing an environmental impact statement in 2004 to evaluate several options, such as putting a moratorium on oyster harvesting or introducing nonnative oyster species, Mr. O’Connell says. The work on the statement will conclude in 2008.
“The objective is to restore the oyster population for ecological benefits and economic benefits,” he says.
Blue crab harvesting, which is conducted from April to November, also has seen declines.
Maryland and Virginia introduced a fishery management plan five years ago to reduce the number of blue crabs caught in the Bay and bolster their numbers, but a rebound has yet to occur, Ms. Reynolds says. However, the crab population fluctuates from year to year, since the species is short-lived and has a large number of offspring, she says.
“It’s unfortunately difficult to make a living from Chesapeake Bay fisheries, even if you’re an experienced waterman,” she says.
Blue crab numbers stabilized last year but have decreased overall, affected by a variety of factors, including water quality, nutrients in the water, dissolved oxygen levels, and weather and climate, says Derek Orner, research fishery biologist for the Chesapeake Bay office of the National Oceanic & Atmospheric Administration Fisheries Service.
Harvesting numbers are variable and cyclic, averaging 70 to 75 million pounds a year, but they have dipped as low as 45 to 50 million pounds, Mr. Orner says. The blue crab harvest is second to the Atlantic menhaden, which provides the largest volume, he says. At one time, the Bay provided half of the national harvest of blue crab, it has now dropped to a third.
“One of the biggest things fishery managers can do is to put regulations on the watermen. You can’t put regulations on weather and climate changes,” Mr. Orner says.
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