Save the Spat

For some, counting oyster spat is right up there with watching golf on TV.  But for the group of dedicated volunteers with the Oyster Spat Monitoring Project, it's like Sunday at the Master's (or close enough).  The Oyster Spat Monitoring Project tries to determine how many offspring an oyster can produce (an important but difficult number to determine) and how many of those offspring survive.  It's easy with land animals, or egg-laying reptiles and birds.  But measuring oyster larvae - also called spat - is a bit more tricky.  It's thought that a female oyster could lay up to 100 million eggs annually.  But pinpointing that number regionally and by species is like looking for a needle in the proverbial hay stack.

The Oyster Spat Monitoring Project

How many of the millions of spat survive long enough to attach to a structure and finally grow into a harvestable oyster?  At the risk of throwing out another bad idiom, I'll turn to our friend at Oyster Stew and marine biologist Troy Alphin.  (Click here to read a previous post about him.)  He developed this program to actually count spat - casting a wide net over the state of North Carolina to account for the long distances larvae can travel before attaching to a host.  His method, along with gritty determination to keep the program alive, is the backbone of this organization.

The Oyster Spat Monitoring Project is an all-volunteer effort coordinated by the Benthic Ecology Lab at the University of North Carolina, Wilmington (UNCW).  Currently, 35 active volunteers meticulously count spat, collected on Spat Racks, up and down the North Carolina coast.  Volunteers are given a packet of recording supplies and a "Spat Rack." After training for a few hours with scientists at UNCW, all volunteers need to participate in the program is a couple of free hours a month (depending on the time of year) and legal access to a dock.   

Oyster Spat Monitoring volunteers receive
a "Spat Rack," (see picture below) a field journal, pencils,
reference guides, and a thermometer.

Volunteers are asked to place the Spat Rack on top of the mud or sand in the mid-intertidal line and attach the Spat Rack to their dock.  If placed in the correct position, the racks should be exposed to air during low tide and submerged during high tide.

"Spat Rack"
Made from PVC pipe, ceramic tiles, cable tiles and a drain hose.
(Image taken by former volunteer coordinator Heather Stoker)

Oyster larvae are able to survive without a host - something to attach to - for about two weeks.  If they don't find something to attach to during those two weeks, they will die.  Desperation often leads to inspiration, which explains why if an oyster can't find another oyster shell to call home, they will attach to just about anything.  

Oysters attach to ceramic tiles on the "Spat Rack."
(Image taken by volunteer Preston Somers.)

The Oyster Spat Monitoring Project uses ceramic tiles to make it easier to count the oysters and is a good substitute for oyster shells.   Every six weeks, the volunteers count the live baby oysters that have attached themselves to the structure and record their findings.  They are also asked to identify and record other organisms, such as slipper shells, mussels and snails, that settle on the ceramic tiles.  Volunteers also collect environmental information such as air and water temperature, water salinity and weather conditions.

What have they learned from this project so far?  I'll let Troy Alphin explain:

"Over the last few years we have found that oyster larvae remain in the water column in the southern area (from White Oak River and areas south) longer than in the central and northern regions of the coast.  So it is not uncommon to get oyster settlement in Nov.  Also, oysters respond to dramatic changes in the weather so that we sometimes see a pulse of larval settlement following coast storms in the late fall."

Smarty pants ... Thanks again Troy!

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 The Oyster Spat Monitoring Project is always looking for more volunteers to keep an accurate count of the oyster larvae in your area.  If you live in North Carolina, have a couple of hours a month, and have legal access to a dock, contact Megan Rudolf at rudolfm@uncw.edu.  To donate to the program, please contact Troy Alphin at alphint@uncw.edu. For more information, visit www.ncoystermonitoring.org.  And, if saving the oysters isn't incentive enough, check out the thank you gift each volunteer received at Christmas last year ... 

Troy Alphin and his family hand-painted
oyster shells to make Christmas ornaments
for all the Oyster Spat Monitoring Project volunteers.