The start of aquaculture can be traced back to ancient Egyptians and Chinese civilizations, where fish were raised in ponds or tanks. While over-fishing, environment (raise in temperature), diseases and sustainability may have not been an issue for the ancient fish farmers, today, however, aquaculture faces significant development challenges. In particular because of the increasing global demand and farming conditions. Thanks to new technology, i.e. oxygen gas generators, introduced during the late 1960s, worldwide fish farming has experienced rapid growth and expanded into several countries. This growth on the other hand has not been without challenges. One of them being the replication of natural conditions.
In the past, aquaculture ponds were carefully chosen based on proximity and specific criteria for optimal growth, such as natural water circulation systems. In modern times, however, fish farming or aquaculture has expanded to a much larger scale, often taking place in offshore or coastal regions that are located remotely, as is the case of salmon farming. In order to replicate natural conditions, aquaculture facilities are often very complex and utilize technologies such as onsite oxygen generators. The success of any modern aquaculture facility depends heavily on aligning these natural conditions, particularly in terms of oxygenation.
Sea cages and provision of oxygen – Aeration
Oxygenation or aeration is crucial in aquaculture, as it supports fish farmers in replicating natural conditions and helps fish with respiration, growth and health. Maintaining optimal oxygen levels is essential to prevent stress, diseases (such as salmon lice), optimal feed ingestion, temperature regulation and overall mortality in farmed salmon. Contemporary salmon farming industry uses two types of aquaculture system methodologies, open and closed systems:
- Open cage systems: Salmon are directly exposed to the surrounding waters. Oxygen availability relies on the natural oxygen levels in the water. Currents and water flow play a crucial role in providing oxygen to the fish. However, due to fish population densities, currents, and temperature rise can result in oxygen depletion. In such cases, additional oxygenation is necessary to maintain optimal and necessary levels.
- Closed cage systems (also known as marine donut): Are designed to provide a more controlled environment. These cage systems allow a better regulation of oxygen levels, as oxygen can be actively monitored and adjusted. The water in closed systems can also be circulated and treated to ensure sufficient oxygenation for the fish, reducing the reliance on natural water currents.
Both open and closed systems require careful monitoring and management of adequate oxygen levels. Factors mentioned earlier, such as fish density, water temperature, feed input and waste accumulation can influence oxygen demand in both types of systems. For instance, increases in temperature lead to a dual effect where the oxygen consumption of the fish increases while the saturation level for oxygen decreases. Salmon farming expert (ref. Fishfarming Expert) recommend that oxygen levels in the cages to not drop below 60% to 70% of the saturation level for extended periods, especially when the water temperature rises above 12 to 14 degrees Celsius.
Bulk delivery or on-site oxygen supply?
To effectively address the oxygen requirements, salmon farmers have two practical options: employing delivered oxygen gas, also known as ‘bulk delivery,’ which is oxygen in liquid form and later gasified, or deploying an on-site oxygen generator, the latter proven to be the most economically viable solution. Every aquaculture facility, however, assesses their own specific needs and requirements such as cost, location, availability, control etc and proceed accordingly. To provide a comparison between liquid oxygen (bulk delivery) and on-site oxygen supply, the table below outlines key factors to consider for each method of oxygen supply.
Liquid oxygen (bulk delivery) vs On-site oxygen generation
| Liquid oxygen (bulk delivery) | On-site oxygen supply | |
| Cost | Expensive due to ongoing purchase of oxygen, storage tanks, rent etc. | Cost savings in the long run by eliminating ongoing purchases |
| Logistics and availability | Relies on external suppliers for timely oxygen deliveries, potential disruptions if supply chain issues arise. Availability may be limited in certain locations, leading to challenges in ensuring consistent supply | Independence and control over oxygen supply and availability. Oxygen production on demand 24/7. |
| Storage and handling | Tailored storage facilities and careful handling for safety | Convenience and immediate access to oxygen without relying on external sources |
| Oxygen purity control | Fixed purity | Adjustable purity |
| Maintenance | Minimal maintenance, mostly focused on the storage tank and vaporizers (gasifiers). | Regular maintenance |
| Environmental impact | Production, transportation, and emissions associated with liquid oxygen contribute to environmental footprint | Reduced transportation emissions and potential environmental benefits |
Apart from for the above outline, it is widely known that on-site oxygen generators are better suited for harsh environments, such as freezing temperatures, where majority of industrial salmon farming facilities are located. On-site oxygen generators help in preventing ice formation, benefitting both salmon and amount of work. As mentioned in the introduction, aquaculture operations depend heavily on successful management of many factors, apart from oxygenation, environment, location, and sustainability are also of crucial importance.
A solution that perfectly aligns with the needs of modern aquaculture operations is OXYMAT’s 10-foot container on-site oxygen generator, designed to optimize oxygen supply while considering the unique demands of the industry.
On-site oxygen generation with OXYMAT 10’ container
OXYMAT’s 10-foot container on-site oxygen generators stands out for their exceptional suitability in harsh environments, high oxygen production capacity, minimal environmental impact, and portability. Highlighted below are advantages in utilizing the container.
- High oxygen production capacity: Adequate oxygen supply is crucial for the health and growth of aquatic organisms. With an impressive oxygen production capacity of 65 kg/h, OXYMAT 10’ on-site oxygen generators provide oxygen purity up to 95% with air factor of 9.0.
- Plug-and-play settings and ease of transport: Fish farming facilities are often located in areas with limited accessibility. Housed within a 10-foot container, OXYMAT on-site generators are highly portable and easy to transport. They can be swiftly put into operation and monitored form a remote location. With a weight of only 6,750 kg, they are ultra-lightweight, and have a footprint that measures (L x W x H) 2,991 x 2,438 x 2,986 mm.
- Low energy consumption and minimal environmental impact: Sustainability is a key consideration in modern aquaculture practices. Recognizing this, OXYMAT on-site oxygen generators are designed with a focus on environmental stewardship. The overall consumption of electric power is 0.6 kW/kg O2.
- Well-suited for harsh environments: The aquaculture industry often faces the challenge of operating in harsh environments, including extreme temperatures and remote locations. OXYMAT 10’ on-site oxygen generators are specifically designed to excel for such conditions. Se image above.
In summary, to meet the growing global demand while ensuring ideal conditions for fish growth, aquaculture, and specifically salmon farming, must replicate natural environment. One of them being oxygenation, which has become essential in both open and closed systems. It has been proven that in comparison to “bulk delivery”, on-site oxygen generators provide a more affordable option in the long run. Along with purities that are adjustable and minimal environmental impact, they offer autonomy and quick access to oxygen. On-site oxygen generators, such as the 10-foot container model from OXYMAT meet the requirements of contemporary aquaculture operations, they improve oxygen production, are portable, use significantly less electric power and are suitable for harsh environments.
FAQ
Oxygen generation technology, including on-site oxygen generators, was introduced in aquaculture during the 1960s. This technology has played an very important role in supporting the growth of the salmon farming industry.
Oxygenation is essential for replicating natural conditions in fish farming, aiding in fish respiration, growth, and overall health. Maintaining optimal oxygen levels prevents stress, diseases like salmon lice, and mortality, and supports temperature regulation and feed ingestion.
Contemporary salmon farming employs two primary aquaculture system methodologies: open cage systems and closed cage systems (also known as marine donuts). Both require careful monitoring of oxygen levels.
Open cage systems rely on natural oxygen levels in surrounding waters but may need additional oxygenation due to factors like fish density and temperature rise. Closed cage systems provide more control over oxygen levels by actively monitoring and adjusting them, reducing reliance on natural water currents.
Salmon farmers have two practical options: liquid oxygen (bulk delivery) or on-site oxygen generation. The choice depends on factors like cost, availability, control, and environmental impact.
Liquid Oxygen (Bulk Delivery):
Expensive with ongoing purchases and storage.
Relies on external suppliers, potential disruptions.
Fixed purity.
Environmental impact from production and transportation.
On-site Oxygen Generation:
Cost savings over time.
Independence and control over supply.
Adjustable purity.
Reduced environmental impact and emissions.
On-site oxygen generators are better suited for harsh environments, like freezing temperatures, common in industrial salmon farming. They prevent ice formation and provide a more consistent oxygen supply, which benefits both salmon and operational efficiency
