Marine Donut

Marine Donut is a cost-efficient floating closed containment system for fish farming. It provides supreme fish quality with minimal environmental footprints. It enables completely new and profitable production strategies.

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Marine Donut is a floating closed fish farm that addresses many of the challenges facing the aquaculture industry and is also economically sustainable.

Good Fish Welfare and Product Quality

Marine Donut is a flow-through system that exercises fish, where the flow can be adjusted according to the farmer's preferences. This recreates the environment that salmon experience in rivers. The dimensions and geometry are designed to suit the preferences of the salmon and provide the right pressure at depth. The design ensures good fish density throughout the facility, not just in the upper part. The exercise also results in very good quality fish meat.

No Escapes and Sea Lice

The tight barrier between the fish and the sea has several advantages. It makes it impossible for the fish to escape, thereby addressing the negative impact on wild fish that salmon farming has in many places. Marine Donut is equipped with water intake from depths below the sea lice belt, avoiding sea lice on the fish. This benefits both the fish and the economy.

Collecting Feed Residues and Sludge

Marine Donut has technology that collects feed residues and fish sludge, allowing them to be handled in a responsible and sustainable manner, rather than being released directly into the fjord.

Good Profitability for Fish Farmers

Marine Donut is packed with technology and sensors that give the farmer full control over all parameters such as water quality, oxygen, and flow. This ensures optimal conditions for farmed fish at all times throughout the facility. Lower fish mortality, faster growth, better feed conversion ratio, and minimal medication costs provide good economics for fish farmers.

Follow the Project: The first Marine Donut has been delivered to SalMar.

Ideal for Post-Smolt Production

Floating closed containment systems can be used throughout the fish's lifecycle, from post-smolt to harvest size. The best economics are achieved by using the facility for post-smolt, from 200 grams to 1.1 kg. The Marine Donut facility is approved for 1100 MTB, providing capacity for 1 million post-smolt fish.

When the post-smolt reaches 1.1 kg, it is transferred to traditional pens or offshore facilities.

The advantage of using floating closed aquaculture facilities for post-smolt is that the time the fish spends in open sea facilities is reduced. As a result, the fish are less exposed to diseases, sea lice, and other hazards in the sea. This improves fish welfare and lice control.

SalMar has purchased Marine Donut

The first full-scale Marine Donut was delivered to SalMar in 2023. Read about the project here.

How it Works:

Marine Donut consists of a closed fish farm unit shaped like a donut (torus). The main structure is made of High-Density Polyethylene (HDPE) and acts as a tight barrier against the external environment to prevent lice infestation and infection into the facility. Marine Donut has floating tubes at the top, stiffening tubes at the bottom, and vertical ballast tanks on the sides. This allows the facility to be raised and lowered. Above the water surface, the facility has a work platform. The facility has a solution for sludge collection and water intake below the sea lice belt. Marine Donut is designed to withstand high exposure to both waves and currents. It is suitable for farming yellowtail kingfish in the tropics as well as salmon and trout in colder waters.

One Marine Donut can hold 1,100 MTB (metric tons of biomass).

Marine Donut can be used in these Production Strategies

Production Strategy 1

A Marine Donut is used for post-smolt for 1,000,000 fish up to 1.1 kg. These are then transferred to five Marine Donuts with 200,000 fish each. There, the fish grows up to 5.5 kg.

Production Strategy 2

A Marine Donut is used for post-smolt for 1,000,000 fish up to 1.1 kg. These are then transferred to five cages with 200,000 fish in each. There, the fish grows up to 5.5 kg.

Production Strategy 3

In areas with a large lice infestation, Marine Donut can work well for the last phase, where the fish grows from about 2.5 kg to 5.5 kg.

Production Strategy 4

Marine Donuts can also be used throughout the production phase from smolt to ready-to-slaughter fish.

Production Strategy 5

Marine Donut is a good alternative for producing post-smolt for off-shore fish farms.

Production Strategy 6

The flexibility of Marine Donut means that it will also work well as a pre-slaughter cage.

Available research results indicates that Marine Donut will give:

Improved production strategy - increased profitability and fish health.
No lice treatment.
Better feed conversion ratio and the possibility of collecting sludge.
Better water quality – increased fish welfare – less disease.
Less mortality – better fish health.
Less «downtime» / more efficient maintenance.
Escape proof.
Increased fish density due to control and monitoring.
Reduced production time / flexibility / optimization.

Nils-Johan Tufte

Partner / CEO

Email E-mail

Phone +47 48 30 48 35

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