In order to make salmon more robust for transfer to sea water, an interdisciplinary research group has decided to strengthen the salmon's heart capacity and health through intensive training.

Training

Farmed salmon are generally in excellent condition. However, based on the hugely beneficial effects training has on humans, scientists wanted to see if the fish's health could improve even more with training.

Benefits to humans through training include strengthening of the heart, muscles, skeleton and immune system and reduction of stress.

"We were concerned that the fish would develop lifestyle diseases," says Senior Scientist Harald Takle at Nofima Marin (formerly Akvaforsk), who headed the research group.

The scientists have found hearts in farmed salmon that differ from the heart form of wild salmon, so the thought that the fish needed training wasn't far off the mark. It was just a matter of starting to train 50 g salmon.

Barcelona

Training is good for humans, but is training also beneficial for juvenile salmon? Jan Helgerud at the Norwegian University of Science and Technology (NTNU) designed a training programme for leading Spanish football team Barcelona as well as different patient groups.

The training programme designed for the fish was a strict training regime and the heart recovery rate was well above normal. Increasing the tank water velocity was the method utilised by the scientists to get the fish to swim faster.

Tiny heart rate monitors

This is a collaborative project involving Nofima, the Norwegian Institute for Water Research (NIVA), the Norwegian School of Veterinary Science, NTNU, Thelma AS and Aakvik Settefisk AS.

"We found the necessary expertise in a variety of places," says Takle. "For instance, we needed to get tiny heart rate monitors made. The monitors, which were developed by Trondheim company Thelma, are inserted in the fish's stomach with sensors attached to the heart".

Training in the tank

The fish in the trial were divided into three groups: one that lived like this type of juvenile salmon normally lives, one that received increased tank water velocity around the clock, and one that in addition received continual "jogging" - a daily spell of high intensity training.

The findings show the fish that trained grew considerably quicker, but that it did not influence feed utilisation.

Why train?

But what is the point of the training?

"We are now conducting tests at the VESO Vikan fish farm to see if the fish with headbands and heart rate monitors have greater powers of resistance to a deadly virus. The findings are extremely promising. Moreover, the fish tackle stress better when they are in better form. Less stress means the fish have greater energy reserves to tackle the challenges of everyday life," says Takle.

The way forward

The new knowledge about juvenile salmon can lead to salmon farmers putting more jets in fish tanks and regulating the tank water velocity.

"In the long-term, we believe that this can make the fish even more robust," he says, adding: "It's just like with us humans, healthier fish thrive better, and this will in turn increase profitability for the salmon farmers."

This project is financed by the Fishery and Aquaculture Industry Research Fund.

Do you want to know more? Contact Scientist Harald Takle,