No ban yet on hydrogen peroxide after Norway shrimp alert
Norway’s fisheries minister Harald Tom Nesvik has said it is too soon to change rules about the use of hydrogen peroxide in salmon farming following new research showing that the lice-killing chemical can also damage shrimp.
In the ongoing study by Renée Bechmann and colleagues at the International Research Institute of Stavanger (IRIS), half of the deep-water shrimp Pandalus borealis that were exposed to a low concentration of hydrogen peroxide for two hours died within three days.
The scientists, who used a concentration of the chemical 100 times smaller than that used in de-lousing operations, have called for the use of hydrogen peroxide to be stopped following the results which they say surprised them.
Important results
But Nesvik told Fish Farming Expert’s Norwegian sister site, Kyst.no, that the results needed more examination first.
“These are important results from brand new research, and something we obviously need to take with us in how we should manage the industry’s use of medicines,” said the recently-appointed minister.
“The Institute of Marine Research (IMR) will review these findings and make an assessment when published on a par with other research.
“We can’t decide here and now if a ban is applicable. There will always be a certain need to use drugs in farming, but we must ensure that the use does not cause unacceptable environmental effects.”
Effect after three days
IMR shrimp expert Guldborg Søvik said the new findings were worrying, and their discovery could be attributable to the way the experiment was set up. She said that in a standard experiment, subjects exposed to an influence were watched for 24 hours and then the experiment ended, whereas researchers at IRIS first saw an effect after three days.
“These experiments performed by IRIS are important for the work we do, but it’s not always easy to transfer results from lab to field, because in lab you have control of all variables and you do not have it [in the field],” she concluded.
A 2016 risk assessment by the IMR of the use of hydrogen peroxide pointed out that since vertical transport of water to deeper levels of fjords is rare, there was little risk to deep-water shrimp, although Norwegian shrimp fishermen have blamed the use of de-lousing chemicals for falling catches.
Breaks down quickly
Hydrogen peroxide is regarded as the least environmentally-unfriendly lice treatment because it is quickly diluted in the sea after use in fish farms and can break down into water and oxygen within minutes, depending on conditions.
The IRIS research project, which started in 2017 and ends in 2019, is being funded by the Norwegian Research Council, the EU and chemical giant Solvay, which manufactures its own hydrogen peroxide salmon de-lousing product, Paramove, in Warrington and in Jemeppe, Belgium.
In addition to hydrogen peroxide, de-lousing products deltamethrin and azamethiphos are also being tested on shrimp.
