II. The Nursery and First Year of the Small Oyster or Clam
OYSTER SEED: Once it is realized the oyster starts out about the same size as the period at the end of the previous sentence, the question becomes how do we grow it out to the size suitable to have for dinner? Or how do we keep track of these sand grain sized living organisms?
First some terminology; just as in farming the land these small bivalves are called seed after they have metamorphosed which included attaching themselves to a surface. Oysters shells (termed cultch and sometimes mother shell) are used in the hatchery and/or placed in areas of the bay where oyster spawning and larval development will possibly occur. Since Bay Center Farms primarily relies on hatchery seed we will trace the seed to adults from this origin.
The picture above shows the cultch bags with oyster shells. Typically there should be around 15 spat per clutch shell and around 250 shells per mesh bag. These bags are being stacked on pallets to be placed upon the intertidal flats so the very small oysters (now termed "spat") can take advantage of the spring and summer growth periods. They will stay in the nursery attached to an old oyster shell and in their protective bags until spring planting. The pallet of bags with each growing around 75 thousand small oysters remain free of the muddy sediments where they would bury and die.
The large boats used for oysters are called dredges or harvesters. Most can haul 500 to 1000 bushels of oysters or bags of cultch with the young oysters growing on the individual shells. The dredge is shown here picking the palletized bags of seed which have been growing in the intertidal for the past 7-9 months. The individual bags will now be split open and the cultch (shell) pieces placed on deck to be transported to the bed where they will grow for the next two summers.
The young oysters (spat) which start out at less than 1/2 mm across the shell, can, in a couple of months of the summer, grow over 5 mm (1/4 inch). That is the size on the clean cultch above.
As they grow they develop shell pigmentation and very sharp margins to the valve (shell). A mass of young oysters as shown on the cultch pieces on the glove and bag (note the thin mesh plastic netting holding the pieces with the attached juvenile oysters). How many oysters can you see in the two pictures?
The Final Two years with Harvest and Shipping >>