35 Years of Blue Crab Research
A blue crab being measured during the winter dredge survey. Credit: Skip Brown
FORTY YEARS AGO this summer, Hurricane Agnes arrived over the Chesapeake Bay watershed in late June and began altering the ecology of the estuary. Coming ashore as a tropical storm dense with moisture, Agnes immediately began unleashing heavy rains and historic floods in the Bay's great rivers. Riding those floods came huge brown loads of sediment that surged down into the mainstem of the Bay and began burying oyster bars and underwater grass beds, two biological communities that were essential to the health of the ecosystem.
The floods of Agnes, however, had little or no effect on another popular Bay species: blue crabs. (Their harvest actually increased over the next two years.) That puzzled two young scientists — one working in Maryland, one in Delaware — who were already rethinking the current theory about where blue crabs spend their early lives. The result would be a new theory that helped solve a long-standing enigma: why do blue crab populations go through so many sudden booms and slumps?
One birthplace of this new paradigm was probably a restaurant in Seaford, Delaware, a midpoint meeting place where once a month scientists Steve Sulkin and Chuck Epifanio could rendezvous and spend a long lunch talking blue crabs. (See The Offshore Odyssey of Blue Crab Science.) Other birthplaces were the new Sea Grant programs recently established in Delaware, Maryland, and Virginia that soon provided support.
In 1977, Maryland Sea Grant began its work with joint funding from the National Oceanic and Atmospheric Administration and the state of Maryland. Its goals included research, education, and extension focused on developing and communicating science-based approaches to restoring and managing key resources of Maryland’s Chesapeake Bay and Atlantic coast.
Once Sulkin and Epifanio were ready to test their new thinking about blue crabs with laboratory experiments and ocean-going research cruises, they were able to turn to Maryland Sea Grant for long-term funding support. One of the new program’s first commitments was funding innovative research on blue crabs, work that would later bring together biologists and oceanographers in cross-disciplinary work. Sea Grant Extension agents soon began providing technical advice to watermen and seafood processors on sustainable fishing, aquaculture, and seafood safety and packaging. (See Crab Processors Get High Tech.)
The Chesapeake has suffered other serious onslaughts besides Agnes, onslaughts like overharvesting of finfish and shellfish, invasive oyster-killing parasites, dead zones of low oxygen every summer, and nutrient overenrichment from the runoff of farms, sewage plants, cities, and suburbs. Managing the ecology of a system under such stress calls for a deep understanding of underlying ecosystem processes, and Sea Grant now has a long history of supporting basic research that investigates problems like nutrient enrichment and explores the resilience potential of the ecosystem.
Funding investments in this kind of research have come from Sea Grant and, of course, from larger institutions like the Environmental Protection Agency and the National Science Foundation — and they have begun to pay dividends. Over the last two decades, research findings have led to new approaches for replanting seagrass beds, rebuilding oyster reefs, and developing a profitable oyster farming industry.
And science-based management has helped reverse declines in traditional fisheries for striped bass and, most recently, for blue crabs, a favorite recreational target for Maryland residents and now the most profitable commercial fishery in the state.
— Michael W. Fincham