“Everything indicates that RAS fish are less robust”

Sindre Nordeide

The fish farming industry has seen a dramatic increase in salmon mortality. Researchers believe it must stem from smolt production. 

Ida Beitnes Johansen is an associate professor at Norway’s University of the Environment and Life Sciences and has researched the salmon heart. She has been a prominent figure in the debate surrounding fast-growing smolt.

She tells SalmonBusiness that it is more than just likely that there is a connection between fast-growing smolt and the problems surrounding the salmon’s heart after sea exposure.

“There is still too little data to say anything for sure, but we have taken random samples, most of which indicate that there is a big difference in the heart morphology between farmed salmon from flow-through facilities and from salmon originating from recycling technology in farming (RAS).”

Ida Beitnes Johansen. Photo NMBU

“In tests carried out on smolts that ran at cold temperatures and under a natural light regime, the heart was more similar to the heart of wild salmon than smolts produced more intensively, with high temperatures and continuous light.”

Beitnes Johansen says that she cannot say anything with certainty about the cause of death we see in salmon today, but that there are such large deviations in the hearts, that everything indicates that it is what one fears.

Bad heart, bad circulation
“It goes without saying that if the salmon has a bad heart, it also has bad blood circulation. It is the same with us humans, that if you have poor circulation, it often causes other ailments or illnesses. We see that in salmon too.”

Beitnes Johansen says that she leads a project funded by NordForsk, where they look at the links between heart health and production practices in the Faroe Islands and in Norway.

“We have monitored heart function in these groups (in the trials) and see a progression in the development of heart disease relatively late in the sea phase. It is reasonable to assume that this also happens in smolt produced in a similar way.”

She, like many others, looks to developments in the Faroe Islands in recent years.

The development she is talking about are figures showing the tripling of mortality among farmed salmon after the North Atlantic nation. The figures correspond to the time when the Faroe Islands switched to RAS in the production of smolt. The increasing numbers are identical to what we have seen in Norway in the last 15-20 years.

Ethical aspect
Beitnes Johansen says that she is experiencing a growing interest in the topic within the farming industry, where she believes that many large players are also looking at the negative development with curious eyes.

“They are especially concerned with heart health.”

She says that there is an ethical aspect that must be taken into account when farming.

“Look, for example, at the broiler chicken that was produced earlier, where the main focus was that the chicken should grow quickly. It’s somewhat the same principle here. The fish must grow quickly and spend as little time as possible in the sea.”

“We have to take animal welfare into account here too,” she concludes.


Related Articles