In recent years, jellyfish have intermittently restricted water exchange in salmon cages. By lifting deep water through a pipe with compressed air, it is now expected to ensure a good environment in the cages even during the jellyfish season, which coincides with the most important growth period.
Bardur Arnaldsson, area manager at Icelandic Ice Fish Farm. Photo: Ice Fish Farm.

Ice Fish Farm has been operating salmon farming in the sea in Reidafjördur on the east coast of Iceland for seven years. The fjord is 45-90 meters deep and has clean, oxygen-rich water, few parasites, and little disease pressure. Because the temperatures are lower than in Norway, the salmon grows somewhat slower, but it is highly appreciated in the markets. However, in recent years, there have been challenges, as, in autumn, there are jellyfish blooms in the upper layers of water, which inhibit water exchange and contribute to the fouling of the nets.

"A group of jellyfish may come into the fjord practically overnight. This is a seasonal natural phenomenon. These jellyfish tend to cover the fish nets, limiting the water exchange in the upper part of the cages. Because jellyfish have poisonous tentacles, the nets cannot be cleaned as usual, resulting in reduced water exchange and oxygen availability. Bardur Arnaldsson, the regional manager for Ice Fish Farm in Iceland, which operates three facilities in the same area, shares this information.

Exploring Various Measures

The increasing problem of jellyfish affecting water exchange in salmon cages. As a response, various measures are being considered, and one solution involves bringing up water from the depths of the cages. This method is effective because measurements of oxygen and temperature at different depths have shown that deep water has a similar temperature to surface water but is richer in oxygen, offering a viable way to ensure a healthy environment for the fish despite the jellyfish challenge.

The goal is to maintain stable oxygen levels in the cages during short, challenging periods when they must limit washing the nets to reduce the fish's exposure to jellyfish, Arnaldsson explains.

Different solutions have been tested, and the choice has been made for a solution called Turbolift. A Turbolift is a vertical pipe with a powerful diffuser underneath, which moves large volumes of water upwards at a modest cost.

"The Turbolift system was the only one that maintained nearly 100% normal operations, even with many jellyfish present. The lift generates a strong upward flow in the pipe, moving water from the bottom of the net up to the surface. This process creates a cascading water flow that facilitates new water exchange and creates overpressure, pushing water upward and out of the net.," Arnaldsson explains.

Working principle of the Turbolift

Good results

The decision to install the Turbolift system in all the cages at the three sites was recently made, and the installations will be completed well before the autumn season.

"We are convinced that the Turbolift system will ensure a healthy environment in the fish cages, which will maintain good fish health, increase appetite, and secure stable oxygen levels at our facilities. This is particularly important during periods when tidal variations are minimal, and jellyfish presence is at its peak," says Arnaldsson.

Furthermore, a variant of the system with mobility has been chosen, facilitated by a container-based compressor solution, which provides the flexibility to use the system more effectively.

" The mobility of the system allows us to move it between different areas, adapting to locations with the highest biomass during the challenging periods that may arise in the autumn. This flexibility enhances the ability to respond to environmental conditions and maintain fish health and productivity," explains Arnaldsson.

Putting the Turbolift in place

Well known

The use of air to lift water is a widely used method to create good water circulation in aquariums and fish farms. Air-lifts are considered to be the most energy-efficient methods for achieving vertical water transport. The Turbolift system can move 4000–6000 cubic meters of water per hour from a depth of 16 meters, using 500–700 liters of air per minute. The energy consumption for this process is relatively low, at 0.5–0.6 kWh per 1000 cubic meters of water, which is considered cost-effective according to Asbjørn Bergheim, the research leader at Bio Marine, the company that supplied the Turbolift.

 Air-lifts are used not only for unclogging fish nets but also to manage oxygen levels in open fish cages, which can fluctuate throughout the day and year. High temperatures and high fish densities can lead to oxygen shortages, which stunt fish growth. Factors like the use of lice skirts and heavy fouling of the nets can significantly reduce water flow and oxygen levels. Therefore, measures may be initiated to maintain a good oxygen condition in the cages.

Jellyfish have caused problems for Norwegian aquaculture in the past six months, leading to losses and forced emergency slaughters of salmon. The issue is mainly due to the string jellyfish (Apolemia uvaria). A suggested solution to reduce or prevent jellyfish from entering the cages is the combined use of lice skirts and the Turbolift system, which can help manage the jellyfish threat effectively.


Using the Turbolift to bring up oxygen-rich water from deeper layers has proven to be an effective measure. It has been observed that the oxygen concentration increases by about 1 mg/l in the top 6 meters of the cages without the risk of gas supersaturation. Additionally, this practice enhances the flow rate in the upper layers of water, and the pumped water has been shown to spread horizontally on the surface due to the uplift from the air bubbles, according to Dr. Bergheim.

Due to low sea temperatures, autumn growth is crucial for Ice Fish Farm. During winter, temperatures usually hover around 2 °C and begin to rise at the start of June. This indicates the importance of the autumn season for the growth of salmon at the farm, given the cooler water temperatures experienced throughout the rest of the year.

In August and September, when the temperature reaches 9-10 °C, salmon at Ice Fish Farm experience significant growth. Maintaining an optimal environment for the fish during this key period is crucial. Bardur Arnaldsson, the regional manager, states that the farm is relying on the lift system to achieve this goal and is currently working on installing electrical connections to the facilities to support this system's operation.

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