The Basic Concept

"Long Line Suspended Bag Culture" for oyster cultivation is a new concept developed by The Last Place On Earth LLC. This is a procedure where standard bags of single oysters are suspended 10 to 14 inches below the surface of the bay.

The oyster bags hang beneath a line of cylindrical floats riding on the surface of the water. The line of floats appear much like a rail road track fastened between two parallel lines of poly-dac marine line attached to an anchor at each end. The lines consist of 76 floats at 2 foot intervals along the line.

Suspended below and between the floats are 75 bags of single oysters. Each bag contains as many as 20 dozen single oysters. Each line when complete will be approximately 165 feet long, including the tether at each end. The anchors at each end of the line are merely a block 2' x 1.5' x 2' of concrete.

The bags are suspended from the surface rather than being supported from the bottom. There are many advantages this system provides over conventional bagged singles production.

1. This keeps the oysters in the prime algae production portion of the water column. Algae grows where the sun can penetrate the water, usually the top 24 inches of water.

2. The metabolism of an oyster increases as the temperature of the surrounding water increases. The warmest water lies closest to the surface. This causes oysters to process more of the nutrients it consumes and thus, grow faster. Temperatures around the Yaquina Bay rarely climb over 80 degrees in the summer so there is less chance of summer closures here than in Southern Puget Sound.

3. This style of production is not dependent upon the condition of the bottom. Usually oysters rest on the bottom. This is OK if the bottom is solid enough to support the weight of the oysters. If the bottom is a mix of sand and gravel it would be considered good for oysters. Mud however will not support the oysters so they sink and die. The Yaquina Bay is mostly mud bottom. At low tide the bags rest on the mud but do not sink because they lift off again as soon as the water rises. They never lay in the mud long enough that the floats won't lift them to the surface as the water returns.

4. The lines float so they can be towed by a boat from one location to another. This is a big benefit when the lines are being constructed. We build the lines, then add the bags, then fill them with seed, and finally move them into place where they will stay and grow. Sometimes it is necessary to move lines from place to place. We are able to test a location with actual product and if we don't like the results for one reason or another we can move the entire line to another location.

5. Because the lines ride at the surface we are able to tend the lines anytime there is enough water level to accommodate our barges. Our barges will set in about 6 or 7 inches of water allowing us to clean lines, reseed or even harvest. We have made a production style that allows us to access to our oysters all of the time except the extreme low tides. We have been able to make our business more routine as far as working standard daylight hours. Usually oyster farmers can only access oysters at low water and are forced to work extremely odd hours that follow the tide cycles.

6. It is the belief of Dr. Anja Robinson (Associate Professor of Fisheries, OSU Marine Hatfield Science Center) and Dr. Shulin Chen, Ph.D., PE, (Assistant Professor Dept. of Biological Systems Engineering- Washington State University) that this system is environmentally friendly and that there are significant benefits created by this floating culture for the surrounding ecosystem.