Maryland's depleted oyster population has more than doubled since 2010, state officials reported Wednesday, giving state scientists hope the bivalves are on track to regain a "substantial foothold" in the Chesapeake Bay after being devastated by diseases over the past 30 years.
An annual fall survey by the Department of Natural Resources found that the number and size of oysters dredged up from more than 250 longtime oyster bars had increased for the third straight year. The oyster "biomass index," as it's known, has reached the highest level measured since around the time the bay's bivalves began to be ravaged by two parasitic diseases.
State scientists credited the increase to a prolonged spell of more than 90 percent of oysters surviving the diseases, Dermo and MSX, which a little over a decade ago were killing off most bivalves. The survey found both diseases well below average, though Dermo remains widespread and is showing an uptick in intensity on some oyster bars in the southern portion of the bay.
Improved survival and good reproduction in 2010 helped boost the commercial harvest in the oyster season that ended in March, with a preliminary tally of more than 400,000 bushels, according to Natural Resources Secretary Joseph Gill.
Gov. Martin O'Malley hailed the survey results, saying they indicate his administration's strategy of expanding no-harvest sanctuaries and planting more than 1 billion hatchery-spawned oysters "is paying off," despite criticism from watermen. But he said the data also shows the need to "stay the course" in order to rebuild the population.
The rebound to date has been largely limited to more southerly waters, with no baby oysters found north of the Bay Bridge. And despite recent gains, the overall population still languishes at less than one percent of historic levels.
Mike Naylor, chief of DNR's shellfish program, said that while oysters' recovery appears strong in spots in both the sanctuaries and in waters still open to harvest, there are still many areas where oysters once thrived that have shown little or no repopulation yet.
"Baywide, no one should get too excited," he said.