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All About Oysters!

South River Federation recognizes that restoring the South River (and the Bay) is contingent on restoring the native Eastern oyster, Crassostrea virginica, a keystone species that provides critical ecological benefits to the Chesapeake Bay and its rivers and creeks!
The Chesapeake Bay's native oyster population has been estimated at less than 1% of historic levels, making restoration critical to help improve the Bay's water quality and increase its economic viability. Oysters are filter feeders and extract access nutrients and suspended sediments and clean the water and support a healthy ecosystem. A single oyster can filter 50 gallons of water a day!

Diseases (parasites MSX and Dermo) are a significant factor in the demise of the oyster but historic overharvesting, poor water quality due to influx in nutrients and sediment runoff also play a role in the decline in oyster population.
South River Federation is collaborating with Chesapeake Bay Foundation (CBF) and other organizations in the recently announced "10 Billion New Bay Oysters by 2025" Campaign and is committed to working together to accelerate oyster restoration efforts. This multiple year partnership will produce 1 billion spat annually in Maryland and Virginia waters that represents a 15-20 % increase in production. The Federation is the leader in oyster recovery efforts in the South River.

In support of re-establishing these bivalve mollusks, CBF established its Maryland Oyster Restoration Center (ORC) in 2002. The ORC houses several large tanks for use in producing juvenile oysters, called 'spat.' It is also home to CBF's restoration vessel Patricia Campbell. The 60-foot boat transports and places hatchery-produced seed oysters onto sanctuary reefs throughout Maryland waters and carries oyster shell and other materials for reef construction. The ORC serves as the central location for all of CBF's oyster restoration activities in Maryland.
ORC houses several large tanks for use in producing juvenile oysters, called 'spat.' These setting tanks are loaded with oyster shell, and then filled with Bay water. Oyster larvae, usually produced by the University of Maryland's Horn Point Laboratory, are then released into the tanks. After a few days, these larvae attach, or 'set,' onto the old oyster shells, at which point they are called 'spat.' CBF produces millions of spat at ORC each year, and with the help of South River Federation and other watershed organizations, transplant them onto restored sanctuary reefs.The Federation's goals is to put one million spat into the South River in 2018.

Restoration Vessel Patricia Campbell

ORC is also the home port of the innovative oyster restoration vessel Patricia Campbell. With its state-of-the-art technology, it is the most advanced vessel in the Bay being used for oyster restoration. Using the Patricia Campbell, CBF staff builds reefs and plants them with juvenile oysters. Among the vessel's highlights is its custom conveyor belt system for planting reef material and oysters with pin-point accuracy. This helps the crew build oyster reefs to exact specifications. Learn more about the Patricia Campbell.

Oyster Gardening

South River Federation's Oyster Growing program allows citizens to grow oysters off their docks in cages over the winter. In 2017, The Federation coordinated approximately 75 growers, taking care of 400 cages of oysters. Gardeners raise the baby oysters from 'spat' to adult (about 7 months), and eventually plant them onto the South River's oyster sanctuary reef. Visit our website for more information and to find out how you can become a South River Oyster Grower.

oyster cages drawing

Are you passionate about the environment? Do you want to uncover mysteries about the streams in the South River watershed?

Be part of a rapid mobilization stream team!

As part of our Church Creek research project, we need to take water quality measurements simultaneously at several Annapolis streams during a rain event. This will better help us understand where the highest concentrations of pollution are occurring.

Come on May 31st at 10am (Location TBD) to attend the training and orientation. We need about 20 people with flexible schedules during weekdays to hike in teams through urban forested areas to grab water samples.  Each attempt only needs 10 people and will only take an hour or two, but it is likely we will have to do this multiple times. We will send out an email alert a couple days before  each attempt based on the weather forecast. We are hoping to wrap up this stream snapshot by the end of June.

This "snapshot" of Church Creek's streams will be incredibly helpful to our research! Results from this exercise will ultimately help to inform us on how to direct our focus to better reduce and treat polluted runoff.

If you are interested in volunteering for this science expedition, have a flexible schedule, and are unfazed by hiking in the rain, please email This email address is being protected from spambots. You need JavaScript enabled to view it. for more information!


Last Week, several Federation members reported reddish-brown water in Pocahontas Creek and Church Creek. Federation staff delivered samples from both creeks for analysis to the Maryland Department of Environment which determined the discoloration resulted from a "very large bloom of Prorocentrum minimum" (over 100,000 cells/mL). The samples from the two creeks also contained Karlodinium veneficum. Both P. Minimum and Karlodinium are bloom-forming dinoflagellates. The MD Dept. of Environment further noted that "a bloom of this biomass is something to watch."

Both algae flourish in nutrient over-enriched waters. Perhaps not coincidentally, Pocahontas Creek and Church Creek have both seen large sediment escapes from construction projects in recent months which have contributed large volumes of nutrients to these creeks. Please alert the Federation if you see any mud floods or discolored water near you and we will ensure that the proper authorities are notified.

Our research on the P, Minimum algae reveals that "shellfish toxicity with associated human impacts has been attributed to P. minimum blooms from a variety of coastal environments" [including the USA] and "Detrimental ecosystem effects associated with blooms range from fish and zoobenthic mortalities to shellfish aquaculture mortalities" The Department of Natural resources refers to Karlodinium veneficum as the "fish-killer"because it produces five varieties of ichthyotoxins which resulted in fish kills in the Middle, Gunpowder, and Bird Rivers in recent years. Thankfully, no evidence of fish kills has surfaced in the South River so far.

The creek samples described above were taken on April 26 and 27, but sampling by MDE today, May 1st, 2018 reveals that the two algae types are still persisting even in the River mainstem off Cedar Point and above the Rt 2 bridge at concentrations that indicate a bloom.

Mahoghany Tides can be subtle. At first glance, they look like muddy water after a rain, but the color is a little orange/red to be caused by dirt. 

Here is a photo of what may be mahogany tide, as seen in Bellport Bay in Virginia, on Thursday, May 26, 2016. Photo Credit: Newsday / Thomas A. Ferrara

Photo of what may be mahogany tide, as

Thank you Brianna Cairco for your work at the Federation, not only as a summer intern, but also helping us do a deep dive into the data for the annual South River report card. She produced dozens and dozens of graphs for us in response to our many questions on why a particular set of data seemed too high or too low. Thanks to her persistance on figuring out "why", we were prepared to answer all our followers questions at the State of the South River presentation! Below is a brief description of her work with the Federation in her own words:
My name is Briana Cairco, I started volunteering at South River Federation in summer 2017, I helped collect water quality data, sample fish, and enter monitoring data into our database. In January I was hired as a database manager to help organize and analyze data to help us better understand changes and trends in the water quality data we have been collecting over the past 7 years. If you can name it, I’ve probably graphed it! I also worked with Jesse, Sarah, and Nancy to produce the lovely 2017 South River and sub-watershed report cards that were recently unveiled. All the hard work and hours crunching data on the computer paid off! Though my position was temporary, I really valued being part of the family and look forward to watching Federation grow, and as time goes on hopefully the water quality in the South River will reflect the hard work and care we pour in to make this watershed a healthier environment.

Over the past ten years, the South River's summer underwater grass beds have come and gone like that college friend who breezes through town once every few years and then you don't hear from again until it suits their undisclosed schedule. When they're around, things are great, and it feels like old times again. When they don't come around, we feel like a little piece of the picture is missing.

In 2017, our summer beds of widgeon grass vanished. Just like they did in 2013, 2011, 2010, and several other years in the past. After seeing better, longer visits from 2014-2016, we at the Federation started feeling like these transient beds of underwater grass could be depended on to show up every year, same time, same place, but with an increasingly large footprint. Alas, mother nature works in mysterious ways.

Is the diminishing water clarity in those areas the cause, or the effect of this disappearance? We've seen rising chlorophyll levels in those areas for three years in a row as well. Perhaps algae is the culprit? We may never know exactly why our underwater friends come and go, but we will continue administering the finest non-profit monitoring program in the State to search for answers, and also to search for our summer beds of widgeon grass.


2017 South River Report Card

This year, the report card included a fold out map with the creek grades on one side and a "Best & Worst" of the River on the other.                                                                                           

2017 Report Card and Fold Out Map plus Best & Worst

This year, the Federation rolled out an interactive data map. It takes a look at whether the river is fishable and swimmable and includes historical data. The data map also provides photos and information about where our restoration projects are located. View the data map at www.southriverdata.net 

Below is a copy of the presentation given by South Riverkeeper, Jesse Iliff and environmental scientist, Sarah Giordano                                                                                                        

Report Card Slide Presentation about 2017 Water Quality Monitoring

See past report cards here.