In 2009 Norwegian fish farms produced over a million tonnes of salmon and salmon trout; nearly 1.2 million tonnes of high-quality feed went into this production. But a considerable amount of feed administered is released to the surrounding waters as respiratory products, faeces and uneaten feed .
This means that a significant portion of the aquaculture industry’s feed is actually wasted on fertilising the ocean with both organic and inorganic nutrients. The value of these nutrients is estimated at NOK 6 billion annually.
Higher economic yield, less pollution
In the project “Integrated open seawater aquaculture, technology for sustainable culture of high productive areas (INTEGRATE)”, researchers have studied whether this waste can be put to use as nutrients for cultivating kelp and/or mussels. The project was headed by Associate Professor Kjell Inge Reitan of the Norwegian University of Science and Technology (NTNU) and received funding from the Research Council of Norway as part of the initiative to promote sustainable seafood production.
“The thinking is that integrated multi-trophic aquaculture (IMTA) will provide significant added value on investments in aquaculture,” explains Dr Reitan, “while at the same time reducing potentially negative environmental impacts.”
Environmental organisations are critical of aquaculture waste as ecologically detrimental.
Kelp can help: many application areas
Researchers carrying out experiments at the research institute SINTEF have documented good growth of kelp cultivated near aquaculture facilities. Mussel cultivation under similar conditions also shows promise.
Kelp can bind large amounts of the inorganic nitrogen and phosphorous discharged by fish farms. One of Norway’s most common macroalgae species, Laminaria saccharina – known as sea belt or sugar kelp – is particularly promising for industrial cultivation for use as a biofuel and feed additive and for extracting its chemicals. Dr Reitan is now collaborating with several companies looking to cultivate kelp for large-scale bioenergy production.
“Development in this area will need to be driven by players in bioenergy and feed production,” asserts Dr Reitan. “I don’t believe the salmon farming industry will get involved in commercially cultivating kelp in the near future, even though integrated production would give the industry a greener profile and enhance sustainability.”
Kelp should grow all year
Based on industrial discharge figures from salmon production in Norway, the researchers estimate the annual potential for IMTA-method kelp at 0.6 to 1.7 million tonnes. The potential for mussels cultivated using IMTA methods is estimated at 7 200 to 21 500 tonnes. Cultivation on this scale would require 82 to 250 square kilometres of marine area. Worldwide, roughly 14 million tonnes of aquatic plants are cultivated annually.
Kelp cultivation needs to be a year-round endeavour in order to be efficient. The researchers at SINTEF have successfully managed year-round artificial cultivation of sugar kelp sporophytes (juvenile plants).
“This makes it possible to exploit the kelp’s strong growth potential when conditions are favourable,” says SINTEF Research Scientist Silje Forbord.
Quadrupling mussel cultivation
The researchers estimate that using IMTA methods to utilise Norway’s salmon production waste nutrients, there is potential to achieve four times the current annual 3 000 to 5 000 tonne harvest of cultivated mussels.
The Research Council’s research programme Aquaculture - An Industry in Growth (HAVBRUK) has launched the research project “Exploitation of nutrients from Salmon aquaculture (EXPLOIT)” to determine how to design and locate kelp and mussel cultivation facilities for optimal utilisation of the aquaculture industry’s waste nutrients.
Further Reports about: aquaculture industry > environmental impact > fish farms > high productive areas > NOK > Norwegian coastal waters > nutrients > SINTEF > surrounding waters > sustainable seafood production > Waste from salmon production
More articles from Ecology, The Environment and Conservation:
Turning wet biomass waste into high-value products
04.12.2013 | ttz Bremerhaven
Study shows reforestation in Lower Mississippi Valley reduces sediment
03.12.2013 | USDA Forest Service ‑ Southern Research Station
Quantum entanglement, a perplexing phenomenon of quantum mechanics that Albert Einstein once referred to as “spooky action at a distance,” could be even spookier than Einstein perceived.
Physicists at the University of Washington and Stony Brook University in New York believe the phenomenon might be intrinsically linked with wormholes, hypothetical features of space-time that in popular science fiction can provide a much-faster-than-light shortcut from one part of the universe to another.
But here’s the catch: One couldn’t actually ...
A star is formed when a large cloud of gas and dust condenses and eventually becomes so dense that it collapses into a ball of gas, where the pressure heats the matter, creating a glowing gas ball – a star is born.
New research from the Niels Bohr Institute, among others, shows that a young, newly formed star in the Milky Way had such an explosive growth, that it was initially about 100 times brighter than it is now. The results are published in the scientific journal, Astrophysical Journal Letters.
The young ...
EPFL scientists have shown how to achieve a dramatic increase in the capacity of optical fibers; Their simple, innovative solution reduces the amount of space required between the pulses of light that transport data
Optical fibers carry data in the form of pulses of light over distances of thousands of miles at amazing speeds. They are one of the glories of modern telecommunications technology.
However, their capacity is limited, because the pulses of light need to be lined up one after the other in ...
NASA's Hurricane and Severe Storms Sentinel airborne mission known as HS3 wrapped up for the 2013 Atlantic Ocean hurricane season at the end of September, and had several highlights. HS3 will return to NASA’s Wallops Flight Facility in Wallops Island, Va., for the 2014 Atlantic hurricane season.
During the 2013 mission, two unmanned Global Hawks flew from Wallops for the first time. The mission highlights included studying the Saharan Air Layer, following the genesis of a tropical storm, finding a unique hybrid core or center circulation in a redeveloped storm, obtaining measurements on the strongest side of ...
Nanosponges that soak up a dangerous pore-forming toxin produced by MRSA (methicillin-resistant Staphylococcus aureus) could serve as a safe and effective vaccine against this toxin.
This "nanosponge vaccine" enabled the immune systems of mice to block the adverse effects of the alpha-haemolysin toxin from MRSA—both within the bloodstream and on the skin. Nanoengineers from the University of California, San Diego described the safety and efficacy of this nanosponge vaccine in the December 1 issue of ...
04.12.2013 | Health and Medicine
04.12.2013 | Materials Sciences
04.12.2013 | Ecology, The Environment and Conservation
04.12.2013 | Event News
12.11.2013 | Event News
29.10.2013 | Event News