System benefits

Name: TOPS Oysters Consulting Ltd
Address: 63 Todds Bush Rd RD1, Nelson, 7071, New Zealand

Utilization of subtidal water space for oyster cultivation

With intertidal water space at or nearing full capacity, future growth of the oyster industry will rely on tapping into under-utilized subtidal waters. TOPS Oysters™is a system primarily designed for deep water longline systems and is well positioned to take advantage of this trend. Due to the minimal structure and flexible continuous tape design of the TOPS Oysters™ technology, the system provides a viable opportunity to expand oyster production into new spaces not suited for caged systems.

Optimal spacing and self-orientation of oysters

Inter-oyster spacing is controlled (adjustable on the tagging machine) at the point of gluing and based on the desired oyster size at harvest. In combination with the self-orientation of oysters provided by the rotating feature of the tag, oysters align and do not touch each other during grow-out which overcomes crowding related competition and stress between oysters. The benefit of this is a balanced growth between meat and shell, with higher survivorship and resistance of oysters to disease compared with caged systems.

As no biofouling control, grading, and biomass adjustments are required, in contrast to caged systems, there is no product handling required from the point of seeding until harvest. This significantly reduces labour costs and allows the utilization of more remote marine sites, which would not be feasible to operate with caged systems that require regular husbandry. TOPS Oysters™could also be particularly desirable to growers who want to target the large/jumbo size oyster market, as apart from water space and associated costs, no further costs in form of additional handling are required to produce a larger size oyster.
As TOPS Oysters™ spat are glued at a small size of 25-30 mm shell length (T15), product handling prior to gluing is also lower in comparison with traditional cement/rope systems that require oysters to be of a larger size for cementing.

With labour costs increasing world-wide, there is a need for increased efficiencies and mechanization in the oyster industry to stay competitive. With mechanization of the gluing, seeding, and harvest processes, TOPS Oysters™ operations can be very efficient. Due to the easily scalable nature of the TOPS Oysters™ technology, once growers have acquired basic equipment, upscaling of production particularly under subtidal conditions can be effectively achieved. This also opens the doors for growers with suitable nursery facilities to become specialized TOPS Oysters™ gluing operators, supplying other growers with pre-seeded tape for grow-out.

While basket systems like the floating basket system can provide good growth of oysters, they only utilize the surface of the water space. TOPS Oysters™, in comparison, allows growers to fully utilize the productive water column, by adjusting the dropper depth to which oysters are grown, to the productive depth of the water column at their site. With TOPS Oysters™, high production efficiencies and yields per unit farm area can be achieved, taking advantage of the full carrying capacity of the site.

TOPS Oysters™ can be used with various bivalve species, such as Pacific oysters, Portuguese oysters, Flat oysters etc. While TOPS Oysters™ is most commonly used to produce Pacific oysters, it also provides an efficient solution to farm bottom living subtidal species such as Flat oysters, in a more productive environment near the water surface, for more rapid growth and higher survivorship, away from seabed predation.
TOPS Oysters™ is most efficiently used for subtidal longline production due to the current seeding and harvesting technology available. However, in some productive intertidal environments, continuous seeding across minimal rebar structures can also be an effective option to produce a premium quality oyster. The TOPS Oysters™ gluing machine can also be operated by one person, to attach tags and glue oysters to just one side of the tape, for this purpose.

Like wild-grown oysters, TOPS Oysters™ are reared without any enclosures, providing free, unhindered water exchange and food supply. This environment mimics the best growing conditions that nature can provide for a quality oyster. Subtidal species such as Flat oysters also benefit from TOPS Oysters™, as the air drying and mechanical handling required with caged system operations can be minimized to just the nursery stage.
Significant capital investment is generally required to set up caged oyster farming operations. As TOPS Oysters™only requires a minimal quantity of baskets for the nursery stage, the capital investment in setting up production capacity is significantly lower.

At the point of harvest, growers have the option to either remove tags or keep them on the oysters as a label, depending on their target market. Individually labelled TOPS Oysters™ allow growers to provide their seller and end consumer with the highest degree of assurance that their product is authentic and safe to eat. Guarantees of provenance and food safety are critical for top end producers with the highest market reputation. .

The TOPS Oysters™ system is the first growing system in the world that provides true traceability of each oyster from spat size all the way to the consumer. You may wonder how? The answer is both simple and smart: each oyster is grown on an individual tag, which acts as a label from the moment the oyster is harvested. The label on which the oyster is grown becomes an integral part of the shell, thereby giving you a true and higher degree of traceability than any sticker label glued on the product at the point of harvest ever could provide for. Traceability of shellfish and more so of top quality raw consumed shellfish like oysters, has several advantages.