In Norway, aquaculture expert Oxyvision and Trelleborg teamed up to develop a system that pumps oxygen into offshore fish farms, helping fish remain healthy and grow bigger.
Oxyvision, a Norwegian startup founded in 2000, made a commercial breakthrough towards the end of 2007 with the Oxyvision controlled oxygen-injection system for offshore fish farms and they already have hundreds of installations around the world.
Pumping oxygen into fish pens to help keep fish healthy and allow them to grow bigger, it is built exclusively with customized Trelleborg rubber hoses, fittings and connectors.
"OxyVision started as an idea to help the growth rate of the fish, reduce their mortality and increase their feed utilization through better oxygen control” says Nils Hovden, Sales Director at Oxyvision.
Oxygen is vital for all animals. In a fish pen, soluble oxygen can be adversely affected by salinity or other factors such as the number of fish, the season, seaweed blooms and so on.
The core problem is that fish need more oxygen as the water temperature increases. However, as the water temperature increases, the available oxygen and its solubility in water decreases.
Oxyvision’s ingenious solution was developed by the company’s two founders, Anders Næss and Martin Gausen, who met while studying for their PhDs in aquaculture at the University of Trondheim, Norway. Their concept was a system that could distribute oxygen over an area as large as 10,000 square meters.
“We approached Trelleborg to see if they could industrialize a rubber hose for the oxygen delivery system” says Hovden. “Trelleborg believed in our idea, and they’ve been very supportive.” “We tried and tried before we found the ideal solution” says Eivind Spiten, Technical Manager at Trelleborg in Oslo, Norway.
“The most difficult things were getting the hardness of the rubber right and finding the right size of micro hole. We needed small holes so that the oxygen would properly diffuse into the water.”
Oxygenating a fish pen with a standard hose in the open sea would create such big bubbles that they would float to the surface and dissipate into the air, bypassing the fish.
The resulting unique OxyVision system consists of a grid of rubber hoses that is sunk about 10 meters down inside a net pen. Pure oxygen is then pumped through the system for dispersion throughout the whole volume of the pen. Micro pores ensure that oxygen is properly dissolved in the water and is spread vertically over large areas.
According to Hovden, when the company was started, little academic or technical research had been done on the effects of low oxygen on fish performance.
Oxyvision, worked with EWOS Innovation, the world’s second-largest feed producer for fish farming and Rogaland Research, an independent Norwegian research institute, to do its own research.
“We found that deoxygenated water has a seriously adverse effect on the growth and feed efficiency of salmon” says Hovden.