The cultivation method and unique site conditions influence the farm design, and required equipment. The design also reflects the farm's location, marine conditions, permitted area size, available working area, and infrastructure.
Lantern net longline system
The oysters can be placed and grown in lantern nets, round cages, or hard-stacked trays.
Lantern net longline set-up at Moss Island Oyster Farm in Peterson Bay, Homer
A floating upwelling system (FLUPSY)
An aerial view of Moss Island Oyster Farm
Lantern nets out of the water
Suspended stacked trays in a floating platform
Suspended tray stacks in a floating raft at Tommaso Shellfish Farms in Shikat Bay, Naukati.
Attached to the working platform is an oyster grow-out raft of suspended trays. Equipped with a boom lifting system, stacks of trays can be easily lifted and prepared for cleaning, tumbling, or marketing.
Floating bag longline system
Blue Starr Oysters' floating longline system
The floats are fairly basic, but effective
The end product: a market-sized Blue Starr oyster
Flip cage systems
The OysterGro system for on water cultivation, which is based on strings of small floating cages, each holding 3,000 oysters in six bags. This is favoured by Seagrove, which operates in Doyle Bay, on the west side of Prince of Wales Island.
A close up of the OysterGro system
Grid line connected to the cages with an easy release connector
Four different mesh bags sizes are available to cater for each growth stage while providing the oysters with protection and adequate water flow
Two main objectives guided our farm design decisions: efficiency and consistency. We can run this farm with three to four people, as opposed to more labor-intensive farming methods that require handling or tumbling the oysters monthly.
Beach intertidal culture system
Beach bags at Blue Starr Oysters in Jinhi Bay, Prince of Wales Island
When the tide falls, the bags are exposed to the air, helping to kill of biofouling and giving the farmer a chance to turn, sort and grade them.
The bags are submerged at high tide, allowing the oysters to feed.
Basic equipment required
Anchors, ropes, culture lines, floats, and buoys are essential basic equipment for all farm designs at sea. The equipment and materials the farmer chooses will depend not only on the site conditions but also on the price and equipment's local availability.
Anchors
Each mooring line is connected to 90 ft of heavy-duty chain, which helps the mooring stay on the bottom and provides stability through tension across the system.
Different size anchors for mooring, grid, and growing lines
Line anchor, paired with a buoy to determine the line's location in the water column.
Concrete anchors are used to stabilize the grow lines and keep the lines under tension.
Different types of bottom anchors (~1,000 lb) are used for oyster and seaweed farms.
Anchors secure the array to the seafloor, maintaining its position and tension. They are connected to the growing line by an anchor line, and sometimes a length of chain, collectively called the anchor rode. Tensioning buoys along the anchor line helps maintain tension during tidal fluctuations by rising in the water at low tide. Tag lines run from the anchor to a retrieval buoy on the surface, aiding in anchor location for retrieval or tensioning. In this picture, there are three types of anchors.
Lines & buoys
A mooring line will be paired with a buoy to determine the line's location in the water column.
Growing lines.
Steel buoys filled with foam are the primary mooring buoys.
Anchor line buoys mark the connection points between the grow line and the anchor line on either side of the array. Typically larger than grow line buoys, they help identify these crucial points.
Some farmers use brightly colored buoys or buoys with hazard markings, known as regulatory marker buoys (RMBs), to mark the perimeters of their sites.