This winter's ice and bitter cold killed from 50 to 80 per cent of the crabs in the upper Chesapeake Bay, severely damaged oyster beds in some areas, and almost eliminated several types of small fish that form early links on the bay's food chain, a University of Maryland research team reported yesterday.

"The phenomenon is unprecedented in my experience on the bay," said Dr. George Krantz, leader of the research team from the university's Center for Environment and Estuarine Studies. "I've never seen anything like it."

"The most unexpected finding is the loss of crabs in deep and shallow water," said Krantz, who said samples were dredged from the bay floor at more than 50 locations in the upper bay. In some areas, scientists found that the ice and cold had virtually wiped out the crab population.

However, he cautioned that scientists have yet to sample the Tangier Sound area and the lower reaches of the bay, which produce much of Maryland's crab harvest. In addition, female crabs annually migrate south to Virginia waters for the fall and winter and may not have been affected by the cold weather.

"The mortality rate is unusally high, but it's not going to be a disaster," said Krantz. "The aby can bounce right back next year."

The oyster population, already weak in much of the upper bay, may also have been decimated in some areas. Hundreds of dead and dying oysters were found in bay tributaries, including Broad Creek, Harris Creek, and the Tred Avon River.

Perhaps of greater significance was the damage found done to several types of small fish - including herring, [WORD ILLEGIBLE], and menhaden - that larger commercial and sport fish feed upon.

"They look like they've suffered 100 per cent mortality, at least in the areas we've sampled," said Dr. Peter Wagner, direcotr of the university's Center for Environmental and Estuarine Studies.

The team also found 30 to 90 per cent destruction of populations of barnacles, mussels, blood worms and small clams along the length of the western shore, the Pautuxent River and the eastern bay.

But white perch, stripped bass and several other types of larger fish appeared to be undamaged by the cold weather, although researchers found surprising few of their number in surveyed areas.

Krantz speculated many of them had migrated into deeper, warmer waters as the cold weather froze much of the bay for the first time in years.

The report, based on findings gathered since last Thursday, was an interim one. A final one is expected early next week when samplings taken by two research vessels in the Lower Bay and Tangier Sound are analyzed.

Tom Wieland, business manager for the Maryland Watermen's Association, said he was surpised that the university had chosen to release preliminary findings. He said that the scientists figures didn't jibe with reports he has received from watermen.

"This kind of upsets me," he said, adding the university had agreed to meet with watermen and other groups before releasing its completed findings.

"Our reports are that from 10 to 15 per cent of the crab crop has been damaged," he said. "Our people have found that the older crabs in shallow water are dead or dying and the younger crabs are making it through."

If the samplings prove correct, it would be the early part of the crab harvest, which begins in April, that would be hit hardest.

"We'll probably be hurting at the beginning of the season until the smaller crabs get some size," said Wieland. "Then, too, we get a lot of crabs during the main part of the season migrating northward from Virginia waters."

He disputed the reports about damage being done to oysters. "We still have a number of oystermen working and making a good living," he said.

The cold weather idled an estimated 1,100 Maryland watermen in January and February as ice sealed off many shellfish harvesting areas. Because of financial hardships caused by the cold spell, President Carter declared the bay region a federal disaster area.