ABOARD THE MISS KAY -- In a steady rain, crew members sort through the pile of oysters on a washboard, separating "markets" and "smalls," "spat" and "boxes" and recording their findings as part of the state Department of Natural Resources fall survey.
They started three weeks ago near Poole's Island, about 18 miles north of the Bay Bridge, and have been working their way south dredging on the Eastern and Western shores to get a picture of the oyster population.
So far, they have found fewer boxes -- the empty shells of oysters killed by Dermo or MSX -- than they had feared. But they also have found fewer spat -- oysters less than a year old -- than they had hoped for.
The mixed results can be attributed to the summer's drought, which stunted field crops and led to saltier water in the Chesapeake Bay and its tributaries. Higher salinities are good for oyster reproduction, but also for Dermo and MSX, the parasites that have ravaged the bay's oyster crop.
North of the Bay Bridge, the survey crew found a mortality rate of about 5 percent to 10 percent, which is about normal, says Mark Homer, head of DNR's shellfish monitoring program. But from Eastern Bay south, the proportion of dead oysters has ranged from 15 percent to 50 percent.
"It's been real spotty," says Homer.
Oysters from the near record spat set of 1997 should be reproducing in great numbers, but apparently they aren't, says Chris Judy, director of DNR's shellfish division.
In two areas near the mouth of the Choptank, they found 800 to 900 spat per bushel. They were hoping for more than 1,000 per bushel.
But predicting oyster supplies is a tricky business.
The conditions in 1997 were not good for oyster reproduction because of heavy rains and a small number of oysters reproducing, Judy says. "But we had a great spat set. And this year you would have expected a good spat set, but it's about average. So go figure."
Oysters, an integral part of Maryland's seafood industry, help restore the health of the bay. They filter pollutants, improving water clarity and allowing the light that is crucial to underwater vegetation to penetrate. Their reefs provide habitats for themselves and other organisms.
The Chesapeake Bay oyster harvest, once at about 24 million bushels a year, has plummeted in recent decades, partly because of overharvesting and partly because of disease. It bottomed out at 79,618 bushels in the 1993-1994 season and started slowly back with the help of oyster recovery programs, reaching 400,000 bushels in the 1998-1999 season.
Maryland has rebuilt oyster bars throughout its portion of the bay and the tidewater tributaries since the 1960s.
Crews place up to 2 1/2 million bushels a year of oyster shells on the bottom to provide places for spat, and they plant "seed" oysters in areas that need more. The state has also carved out oyster sanctuaries.
The rebuilt bars show up quickly on the sonar screen in the cabin of this slightly overgrown workboat. The red line that has been crawling across the screen showing a water depth of 40 feet goes up sharply until it shows only 5 feet and levels off.
John Hess, one of the crew members, pokes a long pole into the water until it hits the oyster-shell bottom with a crunch.
"Five feet," he says. "You're on it."
Capt. Lee Daniels slows the boat as Scott Monzeglio drops the dredge over the side.
A few minutes later, Monzeglio hauls it up loaded with oysters. The scientists separate market-size oysters -- 3 inches from the hinge to the bill -- from spat and dead oysters.
"Market, market, two smalls, 16 smalls, market box, old," calls Robert Bussell, as Mickey Astarb carefully records the findings -- two large enough to go to market, two small oysters, 16 more attached to an old shell, and an empty shell that would have been market size had it lived. It had been dead for some time, judging from the brown muck that had collected on the inside.
Hess, from Crisfield, grabs about a half-dozen of the oysters and begins shucking them and grading the meat on a scale of 0 to 5. In this batch, they are mostly threes and fours, he says, an indication the water is cooling, the oysters are finished spawning and using their energy to grow again.
While the mortality rate has increased, it hasn't gone as high as scientists thought it might, given the increased salinities, and it isn't as bad as it was in 1991 and 1992.
"Back then, we'd pull up the dredge, and it would be just death, death, death," says Judy.
Pub Date: 10/22/99