The health of the Chesapeake received a failing “D” grade from the Chesapeake Bay Foundation, as the group said the estuary showed no improvement since last year in its annual “State of the Bay” report.

The health rating index of 27, on a scale of 100, is unchanged since last year, and is 1 point less than the 28 point ranking the CBF gave the Bay in 2000, when regional leaders signed the sweeping Chesapeake 2000 agreement that called for cleaning up the Bay by 2010.

“Today, more than halfway to the 2010 target date, instead of seeing significantly improved water quality we have a Bay that is dangerously out of balance and in critical condition,” said CBF President William Baker.

“Science has determined that successful, large-scale restoration of the Bay and its rivers is possible, but only if plans are funded, implemented and enforced. Our elected officials must act boldly, and they must act now. Band-Aids will not stop the bleeding.”

To come up with its index, which the group began in 1998, the CBF compares the current status of 13 indicators with what their condition is thought to have been before European settlement. It averages those scores together to come up with the overall index.

A perfect 100 score would represent a “pristine” Bay, which the CBF says is unattainable. But the foundation does say an eventual score of about 70 is possible.

CBF officials have long acknowledged that some indicators are more subjective—such as the measurement of toxins—than others. Nonetheless, it is generally in line with the prevailing view of scientists that the Bay’s condition bottomed out about two decades ago and has made only a modest improvement since then.

Here are the scores for 2005, and the CBF’s basis for changes from 2004:

Nitrogen: 13, up 1 & Phosphorus: 20, up 4

The nitrogen figure reflects the impact of a dry summer, which reduced the amount of nitrogen entering the Bay from runoff. The phosphorus number improved because springtime nutrient loads to the Bay were dominated by the Susquehanna River, which proportionately delivers less phosphorus than nitrogen to the Bay.

Dissolved Oxygen: 12, down 1

The summertime area of “anoxic” water—areas with no oxygen—was among the largest seen in 21 years of monitoring, extending nearly to the mouth of the Bay. This was also the third worst year for overall low dissolved oxygen levels.

Water Clarity: 15, no change

High spring flows of polluted runoff caused poor water clarity in the spring, but conditions improved enough during the summer to keep the overall score unchanged from last year.

Toxics: 27, no change

The most recent data from the EPA indicate that the release of toxics to surface waters reported by industry has decreased in the watershed, but the CBF said additional steps were needed to reduce toxics from other sources, such as stormwater runoff and air deposition.

Riparian Forest Buffers: 55, no change

Although about 3,800 miles of streamside forest buffers have been planted since 1996, the CBF said those efforts were offset by haphazard development which destroys existing buffers.

Wetlands: 42, no change

Regulatory programs and voluntary restoration efforts have helped to hold the line on wetland losses and offset losses that occur through illegal activities and natural factors such as sea level rise. But the CBF warned that large wetland losses loom if the proposed Intercounty Connector highway in Maryland and King William Reservoir in Virginia go forward.

Underwater Grasses: 20, up 2

The increase reflects continued recovery of grass beds in the mid and upper Bay, especially in the Susquehanna flats, where grass beds are at abundances not seen since Hurricane Agnes in 1972. But the CBF noted that grasses continued to decline in the lower Bay.

Resource Lands: 20, no change

Development continues to consume farmlands and forests in the watershed, but the CBF noted that programs to conserve open space got funding boosts in Pennsylvania, Maryland and Virginia this year.

Rockfish: 71, down 2

Although the population remains very strong, there are continuing concerns about the health of individual fish, possibly because of a decline in menhaden—the preferred prey of striped bass—and habitat problems. Surveys show that increasing numbers of fish are infected with mycobacteriosis, an often fatal wasting disease.

Blue Crabs: 38, no change

The spawning stock remains below average, but reproductive success improved last year, and the harvest rate has declined slightly, although it is still above target levels.

Oysters: 3, up 1

Harvests were up this year in both Maryland and Virginia, suggesting an increase in oyster numbers. Also, scientists believe oysters in some parts of the lower Bay are showing signs of disease resistance.

Shad: 12, up 2

Shad restoration efforts continue to show steady progress as the result of stocking programs, fish passage construction and closures of the shad fishery both in the Bay and along the Atlantic Coast.