Bay-area seafood markets are brimming with succulent blue crabs, especially the soft-shell crabs that are a prized local delicacy. But fisheries scientists say this spring's bounty isn't a sign that the Chesapeake contains an unlimited supply.
A report from the Chesapeake Bay Program concludes that watermen are taking as many blue crabs as they safely can without threatening the long-term survival of the creature. There are some signs that more restrictions may be needed.
This year's "blue crab advisory report," completed this month, called the bay's crab population "fully exploited." Scientists found below-average ratios of juvenile crabs and females of spawning age to all the crabs counted, the report said.
Researchers think at least 10 percent of the adult crabs from each year must survive and breed to support the population.
"It's fully fished, and we shouldn't be taking any more crabs than we are now," said Peter Jensen, deputy director of the Maryland Department of Natural Resource's fisheries service.
Rob O'Reilly, head of the group of government fisheries scientists who wrote the report, said Chesapeake Bay watermen's crab harvests have remained fairly stable, averaging about 85 million pounds a year since the mid-1990s. But the proportion of the bay's crabs that are ending up in seafood markets has crept upward slightly over the past three years.
"There's still stability, but there has been an elevation in the fishing rates, and you want to make sure you don't allow that to increase," said O'Reilly, assistant chief of fisheries management for the Virginia Marine Resources Commission. "We need to wait and see if we need stronger conservation recommendations next year. But it would be very preliminary right now to say what that might be."
The experts caution that blue crabs are perhaps the toughest of the Chesapeake's inhabitants to tally, because they hibernate in the winter, migrate the rest of the year and are eaten by almost all of the bay's creatures.
Four scientific surveys
It takes four scientific surveys to cover the bay and the seasons. This year, for the first time, the scientists combined results from the four surveys to come up with their status report.
Blue crab expert L. Eugene Cronin, who has studied the crabs since 1950, said the findings "are based on some assumptions that may or may not be correct," such as the crabs' average life span, still a mystery to science. "I'm not sure we have a good index of [crabs'] abundance yet," Cronin said.
The new report does not attempt to predict the size of this year's crab harvest, which is more difficult than assessing the size and makeup of the whole population, Jensen said.
"There's always that environmental variable that passes almost unnoticed by us humans," he said. "It's much easier to look back and assess what happened than to predict what's going to happen."
Some things about crab behavior are predictable, among them the mass molting that occurs in late spring, which is responsible for the current bounty of soft-shell crabs in local markets. Author William Warner, in his classic book "Beautiful Swimmers," says the molting usually occurs in response to a waning moon, rising water temperatures and "other factors as yet undetermined."
Catches of hard-shell crabs have been better than average in April and May. Jensen said about half a million pounds is usually, harvested in April but that April's catch this year will probably be closer to a million pounds when it is tallied in a week or so. The good harvests could have been caused by a mild winter, when fewer crabs were killed by cold, said Cronin and Jensen.
Bill Devine, owner of Faidley's Seafood in Lexington Market, said the crab supply hasn't reached the peak levels of summer but is better than usual for the time of year.
"You can get all you want," Devine said. "When I go to church on Sunday, I'll ask the good Lord why."
Pub Date: 5/23/98