Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: SUNDAY, May 30, 1993 TAG: 9305300107
SECTION: VIRGINIA PAGE: C-4 EDITION: METRO
SOURCE: Associated Press
DATELINE: ANNAPOLIS, MD. LENGTH: Medium
Sediment that accompanied the freshwater surge could cause an algae bloom that would rob oxygen and sunlight needed by aquatic vegetation. The increased flow of fresh water also could be hard on Chesapeake shellfish such as oysters, which need a certain salinity level to survive.
The meltdown of a March blizzard and unusually heavy spring rains poured 4 percent more fresh water into the bay than Agnes did in 1972, according to a report by the Chesapeake Bay Program. The hurricane devastated the Chesapeake and it was a decade before it fully recovered.
However, the increased freshwater flow that followed Agnes was significantly more intense, occurring over a 12-day period.
Still, the damage this year to bay grasses and shellfish could be significant, said Elliot Finkelstein, spokesman for the Chesapeake Bay Program. Scientists won't know for sure until late this summer, he said Friday.
The Chesapeake Bay Program was formed to supervise the restoration of the bay under an agreement by Maryland, Virginia, Pennsylvania, Washington, D.C., and the federal government.
"There is the potential for problems - potential for changes - but we have to see whether that really manifests itself," Finkelstein said. "I suspect it's going to echo through the system; it's just a question of how long."
"We're anxious," added Michael Hirschfield, senior science adviser for the Chesapeake Bay Foundation, a private conservationist group.
"None of the things that happened . . . are particularly good for the bay. It's a case of wait and see whether it's going to be bad or not as bad as we feared."
Hirschfield said the biggest concern is how the freshwater surge will affect bay grasses, which have been making a slow but steady recovery in recent years. Bay grasses are important because they provide habitat for other aquatic life and convert nitrogen into oxygen.
Noting that clams and oysters were severely affected by Hurricane Agnes, the report warned that oysters cannot survive when the bay's salinity drops below 4 or 5 parts per thousand salinity. Finkelstein said experts won't know for certain until this summer whether this spring's "pulse" of fresh water will drop salinity levels that low.
However, some fresh water could actually help by killing off the MSX and Dermo parasitic diseases that have severely damaged oyster harvests in recent years.
"There's a balance between the effects on the disease versus the effect of low salinity. It's still a little bit of a question mark," he said.
The increased fresh water has dropped water temperatures, which could delay the crab harvest season, and fewer crabs might be found in the upper portions of the bay, the report said.
The study said early indications are that the annual spring phytoplankton bloom has been delayed by the freshwater surge, likely resulting in a reduced food supply for larval fish during the critical days after they hatch.
For swimmers, there's a good side to the freshwater surge. Lowered salinity and increased sediments will likely reduce this summer's population of sea nettles, the stinging jellyfish-like creatures that make wading into the Chesapeake in late summer a dicey proposition.
"One of the nice things about this whole thing is that there will be less sea nettles, so we can all swim this summer," Finkelstein said.
by CNB