Whereas the farming of salmon does assist take stress off wild shares, the feed used to lift the fish nonetheless is not totally sustainably sourced. Which will change, nonetheless, due to nutrient-rich worms that eat available seaweed.
Farmed salmon usually eat business feed containing different sorts of wild-caught fish, together with elements reminiscent of soy, which need to be transported lengthy distances from the farms the place they’re grown. It could be nice if the salmon might simply eat regionally grown seaweed, however in response to scientists from Norway’s SINTEF analysis institute, seaweed would not comprise sufficient fat to assist the expansion of such fish.
With that limitation in thoughts, a crew led by SINTEF scientist Andreas Hagemann appeared to a standard kind of marine worm generally known as the ragworm (Hediste diversicolor).
Though ragworms are omnivorous, Hagemann questioned if they may survive on a food regimen of nothing however seaweed. The farming of seaweed for human consumption is an enormous trade in Norway, however seaweed fronds change into unpalatable as soon as they develop too massive – moreover, imperfect off-cuts of youthful seaweeds are sometimes deemed unmarketable.
In lab exams, it was discovered that ragworms thrived on a food regimen consisting solely of farmed sugar kelp (Saccharina latissima) which might in any other case have been discarded. Moreover, salmon feed made out of these worms was wealthy in Omega-3s, together with different fatty acids and marine proteins.
One potential limitation lay in the truth that the Norwegian seaweed-growing season is comparatively quick, so contemporary seaweed is not obtainable 12 months spherical. Thankfully, the worms readily accepted kelp that had been frozen or acid-preserved, and the fatty acid content material of these worms was just like that of worms raised on contemporary seaweed.
That mentioned, the scientists hope to take issues even additional.
“Sooner or later we will probably be wanting into how the seaweeds might be processed to make them a fair higher meals for the ragworms,” mentioned Hagemann. “We may even see whether or not the worms’ nutrient profile might be enhanced, maybe by combining the seaweed with different sorts of residual uncooked supplies.”
The ragworm-based feed is being developed as a part of the POLYKELP undertaking, which is being carried out in partnership with Norwegian seaweed farming firm Seaweed Options and fish feed producer Marine Bio Options.
Supply: Norwegian SciTech Information