Three important indicators of the health of the Bay showed improvements in 1997, according to information released today by the Chesapeake Bay Program. Underwater Bay grasses increased by almost 6,000 acres, more oxygen was available to fish and crabs during the early summer, and less nitrogen and phosphorus were found in the Bay's waters last year as compared to previous years. Officials also noted that the higher oxygen and lower nitrogen levels were the best on record in 13 years of system-wide monitoring by the Bay Program.

"Overall, this was good news for the Bay's living creatures because it means that there was more oxygen in the water and more habitat available to them during the critical summer months last year," said Bill Matuszeski, director of the U.S. Environmental Protection Agency's Chesapeake Bay Program. "However, this overall good news for the Bay must be balanced against the bad news from last year -- the outbreaks of Pfiesteria in several isolated tidal creeks."

Between 1996 and 1997, Baywide grass acreage increased 5,770 acres or 9%. This improvement continued what was a six-year trend of overall increases from 1987 to 1993, followed by two years of declines in 1994 and 1995 and an upturn in 1996. Currently, grasses cover about 69,238 acres of Bay bottom. However, the current acreage is about one-tenth of the nearly 600,000 acres that were once thought to have covered the Bay floor.

In 1997, grass acreage in the upper Bay increased 27%, the mid-Bay area was up 8% and the lower Bay showed a 3% increase. However, increases in the upper Bay were tempered by a continued decline in grasses in the Tangier Sound area, which showed a decline for the fifth year in a row. The latest decrease marks a 14% decline in Tangier Sound since 1996 and a 48% decline since 1992. [See Fact Sheet for more specifics on Bay grass increases and decreases.]

Restoring the Bay's grasses is one of the top priorities of the Chesapeake Bay Program. In 1993, the Bay Program partners agreed to restore grasses to 114,000 acres by the year 2005. The current total acreage represents 61% of that goal. Underwater grasses are important to the Bay because they produce oxygen; provide a nursery, food and protection from predators for a variety of creatures, including crabs and fish; reduce wave action; reduce erosion; absorb the nutrient pollutants phosphorus and nitrogen; and trap sediments. In order for grasses to grow, sunlight must be able to penetrate the water to near the bottom. Grasses increase in response to water quality improvements that occur when levels of sediments and nutrient pollution are reduced. Grasses also are a good measure of the Bay's health and water quality since they are not under harvest pressure like most of the Bay's other living resources, including fish and crabs.

Recent discoveries of damage to Bay grasses prompted action in both the Maryland and Virginia legislatures in 1998. In Maryland, the legislature adopted laws that prohibit hydraulic clam dredging in Bay grass beds in the Chesapeake Bay and the state's coastal bays. (Virginia never has allowed hydraulic dredging.) In Virginia, the Marine Resources Commission adopted regulations which prohibit clamming within 200 meters of grass beds in Chincoteague Bay (a coastal bay) and regulations which prohibit the placement of new aquaculture structures within grass beds. Also, the Virginia General Assembly directed the Virginia delegation to the Chesapeake Bay Commission to study aquaculture and other activities that could affect Bay grass beds and measures to protect grass beds and report back by next year's legislative session.

Freshwater flow -- always a factor in the state of the Bay -- averaged 41.5 billion gallons per day in 1997, making last year a lower-than-average year for flow. The low flow in 1997 has been cited as a reason for the improved conditions in the Bay. Freshwater flow directly affects both the amount of nutrients delivered to the Bay and the mixing of oxygen-rich surface waters with oxygen-depleted bottom waters. In 1996, the rivers feeding the Bay experienced their highest-ever flows at 87.5 billion gallons per day. Those conditions contributed to increases in the amount of stressed bottom waters, poor dissolved oxygen conditions and higher nitrogen concentrations.

"The Chesapeake Bay is a very complex system, driven by weather and river flow as much as by pollution," said Carlton Haywood, chairman of the Chesapeake Bay Program's Monitoring Subcommittee. "Although 1997 showed improvements over 1996 as far as nutrient concentrations, it will be a few years before we will know if those improvements are part of a trend or are just due to the drought and low flow."

Another snapshot of the Bay's health in 1997 showed an improvement in the level of dissolved oxygen in the water. According to Bay Program monitoring data, which reflects actual conditions observed in the mainstem Bay, 1997 levels of oxygen were among the best since monitoring began in 1985. This improvement is significant for the Bay's living resources because the improved oxygen levels meant a decrease in the volume of Bay bottom water with low oxygen during the summer months. Experts pointed to the cooler water temperatures and low flow as part of the reason dissolved oxygen levels improved.

The Bay Program's dissolved oxygen data focuses on concentrations in the summer months C the time when oxygen conditions become the most stressful for the Bay's living resources. During this time Bay waters are divided into an upper and lower layer. As water temperatures rise in the upper layer, fish and shellfish that would normally retreat to the cooler, deeper waters of the bottom layer of the Bay may be restricted due to low oxygen levels in those waters. This bottom lower layer of water encompasses 40% of the Bay's volume in the summer.

Since data collection began in 1985, the worst summers for dissolved oxygen have been 1987, 1989 and 1996 when approximately 75% of the volume of lower layer waters had dissolved oxygen conditions that were stressful for fish and shellfish. In 1997, less than 50% of the lower waters had stressful conditions.

A third snapshot of the overall condition of the Bay in 1997 showed that the nitrogen concentration for the mainstem Bay was the lowest on record since coordinated Baywide monitoring began 13 years ago. This is due in part to the low flow in 1997. However, the 1997 improvement in nitrogen concentrations does not point to a trend. According to the data, the annual average nitrogen concentration has varied but there has been no detectable trend over the last 13 years. Similarly, no trends have been detected in the Baywide phosphorus concentration, although the 1997 level decreased slightly.