Posts Tagged ‘shellfish’

2015 Harris Creek Oyster Sanctuary Construction

Tuesday, February 10th, 2015

The U.S. Army Corps of Engineers and partners resumed oyster restoration in Harris Creek, Jan. 13, 2015. The project is part of the Maryland and Virginia statewide oyster restoration program, as laid out by the Corps’ Native Oyster Restoration Master Plan that identifies the most suitable tributaries throughout the Chesapeake Bay for large-scale oyster restoration based on physical and biological conditions.

New construction in Harris Creek consists of placing 57 acres of reef in water 6 to 9 feet deep (mean lower low water, MLLW). Similar work in the Tred Avon River is also scheduled to begin this winter, and efforts may occur simultaneously. In the Tred Avon, 24 acres of reef will be placed in water 9 to 20 feet deep (MLLW).

Work includes constructing 1-foot reefs using rock and mixed-shell materials. Constructed reefs will be made of: 1) rock only, (3 to 6 inches in size); 2) combination of rock and mixed shell; or 3) mixed shell only (2 to 3 inches in diameter). The shell comes from processing plants in the mid-Atlantic region and is permitted to be imported and placed in the river. The rock is quarried in Havre de Grace, Md.

Construction is anticipated to end spring 2015. The reefs will be monitored to assess the restoration progress. The State of Maryland has planted more than a billion oysters in the Harris Creek Sanctuary since 2011.

source: U.S. Army Corps of Engineers

Maryland 2013 Fall Oyster Survey

Wednesday, May 14th, 2014

Results of Maryland’s 2013 Fall Oyster Survey indicate populations are continuing to increase. The oyster population has more than doubled since 2010, reaching its highest point since this type of monitoring began in 1985.

The upswing was driven by high oyster survival over the past few years as well as strong reproduction in 2010 and 2012. As a result, oyster harvests have increased, with watermen quickly reaching their daily catch limits during the early part of the season.

“Preliminary harvest reports for the past season have already surpassed 400,000 bushels – with a dockside value in excess of $13 million – the highest in at least 15 years,” said DNR Secretary Joe Gill. “Coupled with the survey results, we have reason to be cautiously optimistic a sustainable oyster population can once again play a vital role in the Bay’s ecosystem and Maryland’s economy.”

In one of the longest running such programs in the world, Maryland has monitored the status of the State’s oyster population through annual field surveys since 1939. The surveys track relative oyster population abundance, reproduction, disease and annual mortality rates, and offer a window into future population levels.

According to the survey, at 92 percent, oyster samples revealed the highest survival rate (the number of oysters found alive in a sample), since 1985 when these measurements began. The Maryland Oyster Biomass Index, a measure of the oyster population, was also the highest since 1985. Oyster reproduction was slightly above the 29-year midpoint, but was largely confined to the lower portion of the Bay.

Oyster diseases remain at relatively low levels. Dermo was below the long-term average for the eleventh consecutive year, with levels similar to 2012, but, continues to be widely distributed throughout Maryland waters. MSX increased slightly from the record-low levels of 2011 and 2012, but remains well below the long-term average.

The survey shows that natural mortality rates within oyster sanctuaries were similar to adjacent harvest areas.

source: Maryland Department of Natural Resources

2014 Blue Crab Winter Dredge Survey

Wednesday, May 7th, 2014

The 2014 Blue Crab Winter Dredge Survey results indicate that female blue crab populations in the Chesapeake Bay have declined below minimum levels, according to the Maryland Department of Natural Resources. The abundance of spawning-age females was estimated to be 69 million, below the minimum safe level of 70 million.

While the crabbing harvest remained at a safe level for the sixth consecutive year, and juvenile crabs increased 78 percent from 2013’s record low, the total abundance of crabs — which include juveniles, and adult males and females – has returned to pre-2008 levels of approximately 300 million.

The results illustrate the inherent variability of the Blue Crab population and the ever-present complexities of managing this dynamic fishery. There are a suite of environmental factors that could be contributing to the low crab abundance, including the unusually cold winter, coastal currents, weather patterns and natural predators.

The long cold winter appears to be one cause of the low abundance level. Low water temperatures resulted in one of the worst cold-kill events since the start of the survey in 1990, causing the death of an estimated 28 percent of adult crabs in Maryland.

The decline in spawning age females will be the biggest factor in determining new management actions by Maryland, Virginia and the Potomac River Fisheries Commission to increase reproductive potential in 2014 and 2015.

DNR and the Virginia Institute of Marine Science have conducted the primary assessment of the Bay’s Blue Crab population annually since 1990. The survey employs crab dredges to sample Blue Crabs at 1,500 sites throughout the Chesapeake Bay from December through March.

The Chesapeake Bay Stock Assessment Committee, supported by NOAA’s Chesapeake Bay Office, is reviewing the data; their 2014 Blue Crab Advisory Report is expected to be released in early summer.

Complete survey results are available at

Maryland Department of Natural Resources

2013 Maryland Oyster Spat Production

Saturday, October 12th, 2013

In October, Governor Martin O’Malley announced that the State and its partners produced and planted a record number of native baby oysters (spat) in 2013.

The University of Maryland Horn Point Lab Oyster Hatchery team in Cambridge set a new national record with the production of 1.25 billion Eastern oyster spat this year.

The University of Maryland Center for Environmental Science’s oyster cultivation facility at Horn Point is a focal point for oyster restoration and research in Maryland and the region.

Harris Creek Sanctuary received 750 million baby oysters, with help from a number of State, federal and private partners. At 377 acres, Harris Creek Sanctuary is the largest restoration project of its kind on the East Coast.

To target restoration efforts, State and federal agencies worked together to prioritize and establish sanctuaries in the most promising areas of the Bay, expanding protected waters from 9 to 24 percent in 2010.

Harris Creek was chosen for the initial large-scale restoration project because its water quality, salinity levels, shape and location all point to a high likelihood of success.

source: MD DNR

2013 Chesapeake Bay Blue Crab Winter Dredge Survey

Tuesday, April 23rd, 2013

Overall abundance of Chesapeake Bay blue crabs dropped from 765 million to 300 million crabs, according to the 2013 Blue Crab Winter Dredge Survey.

Juvenile crabs declined from 581 million to 111 million. The number of spawning-age females increased from 95 million to 147 million, well above the healthy-abundance threshold of 70 million.

Officials cite poor reproduction in 2013 and possible high mortality within the 2012 year-class as contributing factors to an overall decline in the Bay-wide population.

The Chesapeake Bay Stock Assessment Committee is reviewing the data and will begin drafting their 2013 Blue Crab Advisory Report over the next few weeks.

In response to the Blue Crab Winter Dredge Survey, Maryland, Virginia, and the Potomac River Fisheries Commission (PRFC) are pursuing strategies to reduce the harvest of female crabs by approximately 10 percent.

The Virginia blue crab winter dredge fishery has been closed since 2008 and is expected to remain closed for the upcoming season.

sources: Maryland Department of Natural Resources, Virginia Marine Resources Commission

    Chesapeake Bay: Nature of the Estuary