Nova Sea provides an “oxygen feast” for its farmed salmon via new seawater pump technology

Outside its packing facility in Lovund, North Norway, salmon farmer Nova Sea is increasing the oxygen content in its waiting cages by 20 percent courtesy of newly-developed pump technology.

Six waiting cages outside of Lovund have been equipped with the pump device, which provides “an oxygen feast for Nova Sea salmon,” the firm said in a press release. The pump also promotes increased oxygen levels, positively impacting fish and improving capacity, Nova Sea Factory Manager (Lovund) Terje Sølna said.

“20 percent increase in oxygen has a positive impact on fish welfare and the quality of the fish we produce. It also means that we can utilise the current waiting cage capacity better, which in turn leads to improved wellboat logistics and more stable harvesting capacity,” Sølna said.

Because the facility is Lovund is located at the inside of a pier, the inflow of “oxygen-rich, new seawater to Nova Sea’s cages” has been limited. The oxygen level in the cages also decreases, “for natural reasons,” when a wellboat fills them up with 100,000 salmon at an average weight of 5.2 kilograms, the company said in a press release.

All this lead to Nova Sea’s investment in PG Flow Solutions’ high capacity seawater pump called the PG-Subflow. The pump has been installed outside the pier, with a guide pipe pulled through the structure and directing oxygen flow towards the waiting cages, the salmon farmer said. Each hour, 20,000 cubic meters of fresh seawater is pumped towards the waiting cages on the inside of the pier by the PG-Subflow.

“We measure the water quality continuously and have measured a 20 percent oxygen increase in the waiting cages after just 30 minutes of pumping with PG-Subflow. That is impressive,” Sølna said.

The PG-Subflow consists of a high-capacity propeller pump with two counter-rotating propellers. The machine’s propellers are fueled by a separate electric motor. Through the use of frequency converters, each propeller RPM can be optimized to the duty. All equipment making up the PG-Subflow is electronic and suitable for submergence. PG Flow Solutions developed, assembled, delivered, and installed the pump for Nova Sea.

“These are high capacity pumps capable of pumping 20,000 cubic metres of seawater per hour despite the relatively modest 21.5 kilowatt effect per pump, which contributes towards keeping operational costs as low as possible,” PG Flow Solutions Vice President of Sales and Marketing Øyvind Berg said.

Alongside the PG-Subflow, PG Flow Solutions also delivered “the flow pipes that extend from outside pier and through the pier to the discharge point 8-10 meters inside the wall of the pier,” according to Nova Sea, which was responsible for the lifting and foundation work to accommodate the installations.

Berg said Nova Sea is the first company to start using the PG-Sublflow.

“The pump system has been running continuously since mid-July, with very good results. The six waiting cages receive a steady and oxygen rich flow of fresh seawater, but without thrusting the cage nets so that they apply pressure on the fish. We are very pleased with the collaboration with Nova Sea and are already experiencing increased interest in PG-Subflow from other fish farming players,” Berg said.

The daily capacity for Nova Sea’s Lovund facility is 320 metric tons (MT) of live salmon, and 30 MT of fillets, it said.

Photo courtesy of PG Flow Solutions