How it works

• The OBC Durethene® cages are assembled to the desired size; one end is permanently closed using stainless steel hog rings. The other end is closed with bridge pins, which allow for easy opening.
• Special Styrofoam cylinder floats, available in different diameters to adjust floatation to match the growout abilities of the site, are attached to each side of the cages with cable ties at 3-4 points. Note: The matching of the floatation to the weight of the bag contents is very important to optimize growout, control biofouling and for shell pruning.
• Special shock cord is attached to each corner of the cage with hog rings. Cord clips are then attached to the outer end of the cord to enable the cages to be quickly attached and detached from the longline.
• A longline grid harness is made with the desired size rope and replast spreader bars; they are then deployed with desired anchor and center line floatation. Position the line so that at high tide theya re taut and bags in combination with floatation are 50% out of the water. Attention and care must be taken with wind and current direction.

Benefits

• Reduces the growout cycle due to early early spring water surface temperature and increased food availability.
• The surface is usually the most productive part of the water column and by having a surface cage allows for higher growth rates.
• Biofouling control; since the surface is also the area with the highest biofouling challenges, due to the grid design the bags, in grid format, can be flipped over all at once at specific intervals to allow the sun and air to decompose the lower side fouling.
• By having the oysters at the surface the wave action agitates the cages which allows for partial shell shaping (pruning) and beach hardening process (note the size of floatation must match the growout abilities of your site
• Reduces labor and handling cost per unit; efficient biofouling control, wave action cleaning and shaping shells, shorter growout time, all contribute significantly to reduce labor cost compared to other methods.
• Designed for areas of ice, storm or high energy conditions; anchors are added to one side of the grid and it is lower below the ice zone or wave action

Equipment and Setup Cost
Cost for all materials: bags, cord, clips, floats, tie wraps, pins, rings, longline, replast spreader bars	Avg. $1,250 US
Anchors	Locally supplied
Labour	Dependant on region
Total Cost	Avg. $1,600 US

Product output production based on 12 months growout cycle after 5 months in nursery
Assuming 25 cents per oyster
120 oysters per bag x .25 = $30.00 x 100 bags	$3,000
200 oysters per bag x .25 = $50.00 x 100 bags	$5,000
Assuming 40 cents per oyster
120 oysters per bag x .40 = $48.00 x 100 bags	$4,800
200 oysters per bag x .40 = $80.00 x 100 bags	$8,000

Click here for a list of required and optional materials used in the system.

Click here for a business plan for the system.