New Norwegian-produced fish welfare technology is now in commercial production

Aug 30, 2012 by Torkil Marsdal Hanssen
Asia buying new Norwegian technology
New Norwegian technology can now provide precise measurements of conditions in the sea cage. Photo: Institute of Marine Research

In 2009, researchers from the Institute of Marine Research (IMR), the Norwegian Institute of Food, Fisheries and Aquaculture Research (Nofima) and the University of Oslo began refining, integrating and testing new technology for monitoring the environmental conditions in salmon cages.

A sturdy monitoring device placed inside the cage transmits continual readings from different water depths via the to a database for automated analysis. This data gives a fish farmer a complete picture of how his salmon are thriving, online and in real time. Today's cages can be as deep as 30 m or more, so an overview of fish welfare is next to impossible without an automated monitoring system.

How it works

A control unit buoy floats in the centre of the cage. At regular intervals, the unit automatically lowers a profiling probe to the depths of the cage to measure temperature, dissolved oxygen, salinity, chlorophyll (fluorescence) and suspended solids in the water (turbidity). A second probe measures incoming quality and current speed.

To assess the the fish are actually experiencing and how they are reacting to variations in these conditions, an was developed to record fish density at various depths in the cage each time a water profile is taken. The researchers have even developed instruments that provide detailed data on the breathing patterns of the salmon to indicate .

Asia buying new Norwegian technology
A speedometer-type reading of fish welfare makes it simple to monitor environmental conditions in the cage. Screenshot: www.imr.no/welfaremeter

The data from the environmental measurements, fish positioning and stress levels are collated and analysed in models also developed by the researchers. The data are displayed in colours and graphs, or can be viewed on the Welfaremeter, which resembles a speedometer.

Vital feedback

"Assessing fish welfare accurately requires knowing the water conditions down where the fish actually are," explains researcher Lars Helge Stien of IMR.

"We know that can vary greatly at different points within a cage, which single-point measurements do not detect. For example, in-cage oxygen saturation could be at a dangerously low level even when the dissolved oxygen reading just outside the cage is 100 per cent."

The new tools provide a far more accurate picture than was previously possible, making it easier to detect the causes of stress reactions, disease outbreak, increased mortality or appetite loss.

"This technology will enable producers to optimise fish welfare and thus optimise both salmon production and profits," concludes Stien.

Two probe units were purchased by Norwegian producers during the development phase. The first commercial-series units, all of which have been ordered by Chinese producers, are now being manufactured.

Facts about the WELFARE-TOOLS project

When fish thrive, they grow faster and are more disease-resistant and less stress-sensitive. The objective of the project "New tools for online overall assessment of rearing environment, stress level, and fish welfare in Atlantic salmon cage farms (WELFARE-TOOLS)" was to develop technology for a comprehensive monitoring system to ensure the well-being of farmed salmon in their cages.

Explore further: Law of the Sea authorizes animal tagging research without nations' consent

add to favorites email to friend print save as pdf

Related Stories

MIT tests self-propelled cage for fish farming

Sep 03, 2008

(PhysOrg.com) -- A self-propelling underwater cage developed and recently tested by an MIT researcher could not only cut costs for offshore ocean-based fish farms but also aid the movement of such operations into the high ...

Much to gain by optimizing delousing

May 28, 2012

New research shows that the efficacy of delousing efforts is greatly affected by the materials used in constructing a well boat’s tank for mixing the delousing agent. This knowledge has now led to improvements ...

Discovering lost salmon at sea

Jun 23, 2011

Where Atlantic salmon feed in the ocean has been a long-standing mystery, but new research led by the University of Southampton shows that marine location can be recovered from the chemistry of fish scales. ...

Fish cage culture catches on in Nepal

Dec 02, 2011

Researchers supported by IDRC guided the first families into this new venture when the construction of a hydro dam flooded the area in 1982.

Recommended for you

How can we help endangered vultures?

18 hours ago

Zoologists from the School of Natural Sciences at Trinity College Dublin are proposing an ingenious idea to help conserve populations of African white-backed vultures. The iconic birds, which play a critical ...

Scientists work to save endangered desert mammal

19 hours ago

Amargosa voles, small rodents that inhabit rare marshes of the Mojave Desert, have faced dire circumstances in recent years. Loss of habitat, extreme drought and climate change brought this subspecies of ...

User comments : 0