How do we assess the welfare of farmed salmon?
We can’t ask a fish how it feels. Scientists have now compiled a manual for fish farmers and other interested stakeholders on what indicators to use to assess farmed salmon welfare.
A recent research project called FISHWELL has published a 305 page manual on how to assess the welfare of farmed salmon in different production systems and husbandry practices.
The project is a collaboration between the food research institute Nofima, the Institute of Marine Research (IMR), the Norwegian Veterinary Institute (NVI), Nord University in Bodø and the University of Stirling in the UK and received close to seven million kroner from the Norwegian Seafood Research Fund (FHF).
“The goals of the project are to provide the user with correct fit-for-purpose tools for measuring fish welfare, based upon sound science. With this in mind, the FISHWELL team have reviewed the fish’s welfare needs and what scientifically documented welfare indicators are suitable for salmon.” says Chris Noble, the Nofima scientist who has headed the project.
Welfare indicators can be based upon the animal or its rearing environment and examples of these include appetite, the fishes’ behaviour, physiological status, gill condition, fin damage, skeletal status, temperature, water flow rate etc.
Welfare indicators which are suitable for aquaculture are called Operational Welfare Indicators (OWIs) or Laboratory Welfare Indicators (LABWIs). OWIs are practical indicators that are suitable for use out on the farm and can easily be used in tandem with daily operations.
LABWIs require a sample be sent to a laboratory and the test results provide the farmer with a robust indicator of the fishes’ welfare within a reasonable period.
Thorough scientific review
“About 100 different indicators were assessed, and of these about 40 operational and laboratory-based indicators remain. Each of these was then assessed in relation to different production systems and processing procedures,” says Associate Professor Martin Iversen at Nord University in Bodø.
“One of the most important outputs of this review is not only to list the different salmon welfare indicators, but also the scientific justification for using each indicator. It will be interesting to get feedback from the farmers. Does the literature agree with what they are experiencing?” says Lars Stien, a scientist at the Institute of Marine Research in Bergen.
The manual is divided into three parts. The first gives an updated scientific overview of the welfare needs of salmon at different stages of life and the different welfare indicators.
The second part tells us which indicators are most appropriate to use in different aquaculture facilities. The last part provides good advice on how to monitor the fishes’ welfare under different husbandry routines or practices, for example during transport or for harvesting.
“In Part B we have gone through which indicators are best suited for use in seven different production systems. This covers traditional flow-through systems on land and sea cages and emerging systems such as RAS, snorkel cages, submersible sea cages, semi-closed systems in the sea and lice skirts. Farmers can now determine which indicators are best suited to their specific system and how they should measure them in one place.” say Jelena Kolarevic, a Nofima scientist.
Early warning system
“Unfortunately there is no single indicator that alone is sufficient to document good fish welfare. A suite of indicators is therefore needed which together can provide a comprehensive picture of the fishes’ welfare. If one or more of these indicators suggest reduced welfare, the farmers can react before the situation escalates,” says Chris Noble, the Nofima scientist who has headed the project. “This indicator toolbox will hopefully help the farmer use the right welfare tools in the right situation” says Chris.
“The work that has been done is a milestone, and has resulted in a toolbox of welfare indicators that can easily be used and will contribute to farmers being able to document fish welfare better than has thus far been the case. At the same time, it is important to note that the reports do not directly indicate what is considered acceptable or not; this is up to others to evaluate,” says Kjell Maroni, Director R&D, Aquaculture at the Norwegian Seafood Research Fund, which has funded the project.
The manual is in Norwegian and an English version will be published during the autumn. A similar manual for rainbow trout will also be published later this year.