Bay Commission Asks:
Are Blue Crab Stocks Stressed?
Legislators of the tri-state Chesapeake Bay Commission heard a cautionary report on the famed Chesapeake blue crab at their most recent meeting, held May 5, in Piney Point, Maryland. University of Maryland researcher Brian Rothschild told the tri-state body of legislators that while the ongoing Baywide crab survey showed a series of rises and falls, the 1994 data indicated a low harvest, relative to the number of people fishing for crabs.
According to Rothschild, in 1994 the blue crab fishing effort was greater than ever, while the catch remained flat. Rothschild pointed out that figures were tentative, since harvest statistics are still being calculated for the Virginia fishery. In Maryland, the 1994 harvest took a strong dive from the very good landings of 1993.
Resource managers often measure catch against effort, with the expectation that more effort should result in higher catches. If, however, stocks are being fished at capacity, additional effort will yield little additional catch. Such appears to be the case for the Chesapeake blue crab in 1994, though researchers and resource managers alike caution against drawing conclusions based on survey results gathered for less than a decade.
Rothschild and others have been undertaking extensive monitoring of the Chesapeake blue crab stocks since 1991, working with funds from the National Oceanic and Atmospheric Administration (NOAA) and others. The Maryland Department of Natural Resources monitors the upper Bay; the University of Maryland Center for Environmental Science (UMCES) monitors the middle Bay; and the Virginia Institute of Marine Science (VIMS) monitors the southern Bay.
Monitoring takes place each winter, when crabs are bedded down in the mud and remain relatively stationary. To sample the bottom, researchers use a metal dredge like the one used in Virginia for winter harvesting of crabs (See Marine Notes, February-March 1994). Rothschild noted that the survey gives resource managers data that are independent of harvest statistics (which are affected by variables in fishing effort and success rates).
W. Pete Jensen, head of Tidewater Fisheries for the Maryland Department of Natural Resources, reported that Maryland had established a Blue Crab Steering Committee, and that the state was keeping a close eye on the winter crab survey, the crab harvest and other key indicators. Crabbers, he said, are now required to keep a daily log of their catch, which they turn in each month. "Our thinking is this," said Jensen, "we want to react before there is a crisis." Waiting until a commercial species drops below critical levels before acting, he said, ultimately costs everyone much more in social and economic impacts.
Jensen said that he is aware of the ripples created by potential management decisions. "Even discussing additional controls on the crab harvest can cause concern," he said. He described telephone calls from seafood distributors asking whether or not they should be planning to take their businesses elsewhere, if the Chesapeake's blue crab harvest should fall. For now, Jensen said, Maryland is remaining quite cautious about the future. Jack Travelstead, head of the Virginia Marine Resources Commission's Fisheries Management Division, echoed Jensen's concern, and said that his agency had a great deal of confidence in the Baywide winter crab survey now in place.
At the end of the session, Jensen announced to the Commission that Dr. Brian Rothschild, the University of Maryland researcher who has helped with much of the stock assessment work for blue crabs and other species, would be leaving Maryland. Dr. Rothschild, who has accepted a position with the University of Massachusetts, as director of the Center of Marine Science, Environment and Technology, has served as a faculty member and researcher at the UMCES Chesapeake Biological Laboratory since 1980.
Crabs are big business in the Bay - annual harvests of some 100 million pounds bring about $186 million to Maryland and Virginia. As effort increases, resource managers worry about fishing pressure, especially on female crabs, which are now increasingly making it to market alongside male crabs, or "Jimmies."