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What are the benefits of SEAPA baskets over fabricated mesh?

SEAPA baskets are specifically designed and manufactured for use in oyster farming. The baskets have a snap together design, removing the need for cable ties holding the baskets together and making their construction less time consuming than other methods. Their injection molded production and cylindrical design gives the baskets ample strength and the ability to handle even the most exposed farming regions. The original SEAPA baskets manufactured in 1998 are still in use today in many locations. SEAPA baskets are the first, and longest lasting injection molded oyster basket in the market

SEAPAS baskets also have the benefit end caps with doors, which allow the farmers to get quick and easy access to their oysters as well as giving farmers the option of automating their grading and stock holding methods.

Are SEAPA baskets easy to put together?

The baskets are designed to snap together for ease of use. The baskets tube and end caps attach firmly and easily into each other, without the need for cable ties, and the SEAPA clips lock into the top of the basket. A complete basket takes about one minute to put together and a person who is experienced in constructing them should be able to go at this pace consistently across the day.

Detailed instructions on construction of the baskets can be found under Assembly info.

How many baskets will I need to develop a hectare of water?

On average you will get approximately 124, 15L baskets per 100m long line. This calculation is based on 3m spacing between the posts and 4 baskets between each set of posts. The total number of baskets per hectare will be dependent on how many lines you are willing to construct per hectare of development. However, you can base calculations on 44 lines per hectare, which equates to about 5,500 baskets. This is often subject to government regulations.

For long line use, each basket consists of:

  • 1 Tube
  • 1 end cap
  • 1 end cap with door
  • 2 Clips

The amount of SEAPA line, outer sleeve and riser clips will depend on your specific development requirements. However, we are more than happy to offer recommendations.

How do I construct a long-line?

In Australian conditions, most farmers construct their long-line using a hardwood timber or pine that has been treated for oceanic conditions, commonly known as H6 grade marine treated permi pine. More recently, there have been a number of plastic alternatives entering the market.

The intermediate posts that hold the line should be 75mm in diameter; this also assists in holding the oyster punt in rough conditions. The strainer posts at each end, which hold the line tension should be between 100mm and 150mm in diameter depending on the type of material, the hardness of the seafloor and the tension at which you wish to strain your line. If larger posts are too difficult to drive in, one strainer for each cable at the end of the rack is recommended.

Does the system work in windy/ rough conditions?

Yes. Farmers in Australia have found that they are able to farm in more aggressive areas using the system compared to their traditional fixed rack system. This is because the system is designed to move when it encounters wave action, which means that the energy of the wave is absorbed through the system which results in less damage to the stock and infrastructure.

The  long-line system uses the wind and wave action to assist the farmer in management of stock. Depending on the wind conditions the farmer is able to rumble, clean, control the shell growth, maximise the meat condition and present a consistent shaped oyster.

What rise and fall of tide do the baskets work best in?

The system is reasonably adaptable to the rise and fall that is experienced in a given area. The minimum rise and fall required for the system to be effective is approximately 0.5m and the system should be effective in any situations were a larger tide differential is experienced.

In areas of smaller tidal movement, it is advised that post clips are placed as close together as possible (touching), which will allow line movements in 100mm increments. Obviously, for areas with larger rise and fall, the clips can be placed further apart eg, with one clip length between post clips to allow for infill later if required.

How long does it take to construct a long-line?

If all components are prepared on shore prior to racking, ie line threaded through outer cable, post clips nailed to post, 4 people are able to assemble 4 100m lines in 4 hours. However, if you are working on an extremely hard seafloor this process will take longer.

How should the site be constructed relative to the wind?

Ideally the site should be constructed perpendicular to the prevailing wind and tide direction. You may not always be able to construct your site perpendicular to both wind and tide direction, so some compromise may be required. By constructing your site in this manner it will allow all oysters to have greater access to the nutrient flow and will spread the oysters more evenly in the basket.

How many times do you adjust the cable?

One or two adjustments are generally made whilst stock is in each of the four mesh sizes. Generally freshly graded stock, when placed in the next larger mesh size, will be hung low for the first four to six weeks to promote shell growth, the raised to clean and harden the shell prior to the next grade. If stock is grown from spat you can expect to handle/grade your oysters between 6 and 8 times during the grow-out cycle. This is a general practice for the farming of Pacific Oysters (C. Gigas). Stock handling practices may differ depending on site location and species of oyster grown.

How many oyster are placed in each mesh sizes?

In Australia, the 15L 20mm, 12mm, and 6mm baskets are generally filled to 1/4 to 1/3 full and are next handled once basket reaches 2/3 full. This allows for good stock management practices and timely grading. This is equivalent to approximately 60 oysters in a 20mm baskets, 200 in the 12mm and 1,000 in the 6mm

Feedback from farmers suggests that 3mm baskets should initially be filled with approximately 6,000 oysters which equates to approximately 1 L of 6mm oysters.

Remember Less is Best, and double the size oyster to mesh.

Do oysters ever grow into the mesh?

No. The unique design of the SEAPA basket offers no sharp corners in which oysters are able to attach. The rumble action when stock is raised will also help to eliminate soft shell growing through the mesh.

How long does it take to grow an oyster to market size in Australia?

The average Pacific oyster (C. Gigas) takes approximately 24 months to grow from spat to market size (approximately 60-70mm), however this may vary to each area and all depends on your market

Why should a farmer reduce their stocking density on their farm?

By reducing stocking density, farmers may be able to increase their productivity as well as the quality of the product for the market. A number of leading farmers in Australia who have reduced their stocking density are increasing revenue per hectare per year as a result

How do your baskets adapt for sub-tidal use?

As shown on the farming systems page, our baskets are used for various farming applications. To use our baskets sub-tidally they are stacked on top of one another using the Premium End Caps. They are then attached together using a rope threaded through the specifically designed holes around the Premium End Cap frame. If using in aggressive environments with high wave action, it is recommended to construct a stainless steel frame which eliminates the baskets from moving.