``Isn't this a beautiful fish?'' he said, avoiding the young predator's long snout. ``I'm so glad to see a pike.'' Then he carefully set the fish back in the water and watched it knife away.
For two decades, Williams has been plumbing the depths of the Chesapeake and its tributaries, trying to measure the health of the complex estuary by what he can see and touch. Every netful tells a story. The return of the pickerel to this northern corner of the bay was a good sign, demonstrating that plentiful underwater grasses were back, once again providing cover for young pike and plenty of forage fish that thrive there.
Now, Williams and other bay scientists are using a new system to better evaluate the state of the bay. The bay foundation has designed an ambitious ``health index'' as a kind of environmental report card on the Chesapeake, comparing a dozen factors today to their condition nearly 400 years ago, when English adventurer John Smith first sailed up the bay and chronicled what he saw.
The first grades are in. They show that striped bass are thriving, oysters are in desperate trouble, and pollution has deeply degraded the bay. They also show that human development has profoundly affected the tributary streams and rivers throughout the 64,000-square-mile Chesapeake watershed, which stretches from Cooperstown, N.Y., through central Pennsylvania to Richmond, Va., and into West Virginia and western Maryland.
The overall score for the health of the Chesapeake: 27, on a scale of 100.
That actually represents a modest improvement since the mid-1980s, said William C. Baker, president of the Chesapeake Bay Foundation. If a similar report had been done in 1983, he said, it would have shown a score of about 22.
``We're looking at a fundamental shift,'' Baker said. ``We're moving from stopping the decline to recovery.''
Baker said the new index, by providing specific measurements of specific indicators, would provide a tool for saving the bay. Finally, he said, there will be a way to assess changes that is more definitive than simply ``better'' or ``worse.''
The new index serves as both a rear-view mirror and a crystal ball, showing how the present compares to the past and providing a path to the future. The Bay Foundation, a privately funded conservation group, has set numeric goals to measure progress by 2005, when it wants the Chesapeake to have a health score of 40.
Improvements in water quality and fish populations feed off each other, creating what Baker refers to as a ``vicious cycle in reverse.'' More oysters, for instance, would reduce sediment, which would improve habitat for more oysters, which would further reduce sediment.
``You need better conditions to come back and help improve conditions,'' Baker said.
Of all the changes in the bay since Europeans arrived, perhaps the most troubling is the decline in oysters. Oysters are efficient filters, removing sediment and pollution from the bay as they feed. They also eat microscopic plants that otherwise cloud the water. And the piles of oysters that once formed extensive reefs rivaled coral reefs as prime underwater habitat for other fish and shellfish. Now, they are little more than mounds.
Over-fishing and increased sediment in the bay have cut the oyster population in the Chesapeake a hundredfold since the 1870s. Despite some success with planting young oysters, only about 1 percent of the once-plentiful shellfish remain, and today's oysters are much smaller. The current oyster catch in the bay is about 200,000 bushels annually, up from less than 100,000 bushels four years ago, but far from the 20 million bushels caught a century ago.
``The loss of 99 percent of the oysters has had an impact, obviously, on water quality,'' said Bill Goldsborough, senior scientist for the Chesapeake Bay Foundation. ``Try to imagine the Florida Keys with 99 percent of the coral gone.''
To restore oyster populations, the Bay Foundation and the Virginia Marine Resources Commission last year bought 2,500 bushels of healthy oysters harvested from Tangier and Pocomoke Sounds in the lower bay by local watermen and transplanted them onto ``sanctuary reefs'' in the Great Wicomico and the Piankatank Rivers on Virginia's western shore, and in Pungoteague Creek on Virginia's eastern shore. In 1996, 2,300 bushels were similarly transplanted, which resulted in a hundredfold increase in the number of young oysters on nearby oyster grounds.
Conservationists are also encouraging bay residents to grow ``oyster gardens'' alongside their docks to provide oysters to plant on sanctuary reefs. So far, there are more than 500 such ``gardens'' around the bay.
These were the scores in the first health index, based on a 0-to-100 scale, with 100 representing pristine, pre-colonial conditions:
* Oysters, 1. With only about 1 percent of historic population levels remaining, oysters are a key indicator of a troubled bay.
* Shad, 2. These migratory fish have been severely depleted by dams and other obstructions in the rivers to which they return to spawn. Their numbers are estimated to be 2 percent of their colonial-era populations. Efforts to build fish lifts and ladders at dams on the Susquehanna River in Pennsylvania and the James River in Virginia give scientists cause for guarded optimism.
* Underwater grasses, 12. Plants such as eelgrass, wild rice, and widgeon grass provide food for birds and mammals and offer vital hiding places for young striped bass, pickerel, molting blue crabs, and other fish and invertebrates. The plants help remove excessive phosphorus and nitrogen and suspended sediment from the water and retard shoreline erosion. There are about 67,000 acres of submerged grasses now, up from a low of 30,000 15 years ago, but far from the 600,000 acres believed to exist during colonial times.
* Dissolved oxygen, 15. Dissolved oxygen in the water is essential for fish and shellfish. The levels have been seriously reduced by increases in nutrients such as nitrogen and phosphorus that stimulate large, troublesome algae blooms.
* Water clarity, 15. Murky water is an indication of excess sediment and nutrients. Excess nitrogen and phosphorus levels result in algae growth that clouds the water. In many places, there is not enough light penetrating the water to permit underwater plants to grow. As recently as a century ago, underwater grasses grew in nine feet of water, compared with three to four feet today.
* Phosphorus and nitrogen, 15. High concentrations of phosphorus and nitrogen kill much of the life in the bay. Fertilizers and manure on upstream farms have drained phosphorus into the Chesapeake, and nitrogen arrives from sewage- treatment plants, air pollution and storm drains. The removal of phosphates from detergent in the 1980s helped reduce the amount of phosphorus, but scientists estimate that there is still seven times as much phosphorus and nitrogen in the bay as there was in colonial times.
* Toxics, 30. Commercial, industrial and residential run-off often carries toxic chemicals into tributaries and eventually into the bay, where they can accumulate over time and kill fish, plants and shore birds.
* Wetlands, 43. Wetlands are prime habitat for birds and amphibians, and they play a pivotal role in controlling floods and trapping sediment, nitrogen and phosphorus. The three bay states (Maryland, Virginia and Pennsylvania - the Susquehanna River feeds the bay) have lost an estimated 57 percent of their wetlands since colonial times, declining from about 3.5 million acres to about 1.5 million acres.
* Crabs, 50. Heavy fishing and reduced grasses have cut the number of crabs at least in half. Crabs now are smaller, and their abundance varies widely from year to year.
* Forested buffers, 53. Forests along streams and rivers that feed the bay prevent fish-killing erosion and help keep waters cool. About 53 percent of the 110,000 miles of streams and shorelines still have forested buffers.
* Striped bass, 70. A success story. Striped bass, or rockfish, are more plentiful than at any time since good records started being kept in the 1960s. The return of the fish from a 1980s collapse is largely due to a widespread ban on fishing during the late 1980s. Concerns remain that there are not yet enough old, large fish and that a persistent disease afflicts many stripers. And a favorite food of rockfish - menhaden - has dwindled, raising concerns that the bass population may fall again.
By 2005, the foundation hopes to meet these goals for improving the quality of the Chesapeake:
* Increase the oyster population by 10 percent.
* Reduce the use of toxic chemicals throughout the watershed by 50 percent.
* Improve water clarity enough to allow sunlight to penetrate six feet during growing seasons for underwater grasses.
* Reduce the loss of open space. The target is to reduce land lost to development by 25 percent, which would be about 22,500 acres a year.
* Reopen 1,500 miles of rivers to migratory fish such as shad; that means removing dams or building lifts and ladders around them.
* Add 125,000 acres of wetlands.
* Add 160,000 acres of underwater grasses.
* Restore 1,500 miles of forested buffers along streams, rivers and shorelines.
* Raise oxygen to healthy levels (five parts per million) in spawning and nursery areas and to three parts per million in other areas.